First node, second node or third node and methods performed by same

Abstract

Various embodiments of the present disclosure provide a method performed by a second node in a communication system, comprising: sending a first message to a third node or receiving a third message from the third node, the first message comprising first information related to protocol layer reset and / or second information related to TA measurement, the third message comprises fifth information related to protocol layer reset and / or sixth information related to timing advance (TA) measurement; sending a second message to the first node, wherein the second message comprises third information related to protocol layer reset and / or fourth information related to timing advance (TA) measurement; wherein the first information or the third information or the fifth information is used for determining a protocol layer reset operation associated with a first cell; wherein the second information or the fourth information or the sixth information is used for determining a measurement behavior associated with the first cell; wherein the first cell comprises at least one of a serving cell, a target cell and a candidate cell.

Description

Technical Field

[0001] The present disclosure relates to the field of communications, and more particularly, to a method performed by a first node, a method performed by a second node, a method performed by a third node, a first node, a second node, and a third node. Background Art

[0002] In order to meet the increased demand for wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or quasi-5G communication systems. Therefore, 5G or quasi-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems."

[0003] Wireless communication is one of the most successful innovations in modern history. The number of subscribers to wireless communication services recently exceeded 5 billion and continues to grow rapidly. The demand for wireless data services is growing rapidly due to the increasing popularity of smartphones and other mobile data devices (e.g., tablets, laptops, netbooks, e-book readers, and machine-type devices) among consumers and enterprises. In order to meet the high growth of mobile data services and support new applications and deployments, it is critical to improve the efficiency and coverage of the wireless interface. Summary of the invention

[0004] According to one aspect of the present disclosure, a method performed by a second node is provided, the method comprising: sending a first message to a third node or receiving a third message from a third node, the first message including first information related to a protocol layer reset and / or second information related to a timing advance TA measurement, the third message including fifth information related to a protocol layer reset and / or sixth information related to a timing advance TA measurement; sending a second message to the first node, the second message including third information related to a protocol layer reset and / or fourth information related to a timing advance TA measurement; wherein the first information or the third information or the fifth information is used to determine a protocol layer reset operation associated with a first cell; wherein the second information or the fourth information or the sixth information is used to determine a measurement behavior associated with the first cell; wherein the first cell includes at least one of a serving cell, a target cell and a candidate cell.

[0005] According to the method provided by the present disclosure and executed by the second node, the first information, the third information, or the fifth information also includes at least one of the following: a cell identifier for indicating a cell associated with the first cell and which does not require a protocol layer reset; a cell identifier for indicating a cell associated with the first cell and which requires a protocol layer reset.

[0006] According to the method provided by the present disclosure and performed by the second node, the second information, the fourth information, or the sixth information also includes at least one of the following: a cell identifier for indicating a cell associated with the first cell and for which TA measurement is not required; a cell identifier for indicating a cell associated with the first cell and for which TA measurement is required.

[0007] According to the method performed by the second node provided in the present disclosure, the first message also includes at least one of the following: indication information for indicating that the third node needs to retain or release the configuration; configuration information associated with synchronization, used by the third node to trigger the first node to obtain the synchronization information of the target cell or candidate cell in advance; configuration information associated with the reference signal, used by the third node to configure the measurement of the reference signal; reference configuration information, used by the third node to generate the configuration information of the candidate cell; indication information for indicating whether the third node needs to perform a protocol layer reset, and indication information for indicating whether the first node needs to perform TA measurement; configuration information of the source cell, including the configuration information of the first node in the source cell; first default configuration information, including configuration information used by the third node when it is unable to determine whether a protocol layer reset is required.

[0008] According to the method provided by the present disclosure and executed by the second node, the configuration information associated with synchronization includes at least one of the following: first synchronization configuration information, including configuration information related to the first node obtaining the synchronization information of the target cell or the candidate cell in advance; second synchronization configuration information, including configuration information related to the first node obtaining the synchronization information of the target cell or the candidate cell through a random access process; configuration information associated with the beam, used to indicate the beam used when the first node sends a signal.

[0009] According to the method performed by the second node provided in the present disclosure, the first synchronization configuration information or the second synchronization configuration information includes at least one of the following: frequency domain indication information, used to indicate the frequency domain information of the first node sending a random access signal; sequence-related information, used to indicate the sequence used for the sent random access signal, and a time alignment timer, used to indicate the effective time of the time advance; a random access channel RACH general configuration, used to indicate the general configuration information used to send a random access signal; a RACH dedicated configuration, used to indicate the dedicated configuration information used to send a random access signal.

[0010] According to the method performed by the second node provided in the present disclosure, the configuration information associated with the reference signal includes at least one of the following: first signal configuration identification information, used to identify the configuration of the signal measured by the first node; first resource information, used to indicate the resources used by the measured signal; configuration information of the synchronization signal block measurement timing configuration SMTC, used to indicate the configuration information of the synchronization signal block SSB of the cell.

[0011] According to the method performed by the second node provided in the present disclosure, the second message also includes at least one of the following: information for indicating the configuration that the first node needs to retain or release; second default configuration information, including configuration information used by the first node when it is unable to determine whether a protocol layer reset is required; configuration information of layer 1 / layer 2 triggered mobility LTM, including configuration information of LTM candidate cells.

[0012] According to the method performed by the second node provided by the present disclosure, the third message also includes at least one of the following: third default configuration information, including configuration information used by the first node when it is unable to determine whether a protocol layer reset is required.

[0013] According to one aspect of the present disclosure, a method performed by a third node is provided, the method comprising: receiving a first message from a second node, and based on the first message, determining whether to perform a protocol layer reset and / or determining whether the first node performs TA measurement; or sending a third message to the second node, wherein the first message includes first information related to the protocol layer reset and / or second information related to the timing advance TA measurement, and the third message includes fifth information related to the protocol layer reset and / or sixth information related to the timing advance TA measurement; wherein the first information or the fifth information is used to determine a protocol layer reset operation associated with a first cell; wherein the second information or the sixth information is used to determine a measurement behavior associated with the first cell; wherein the first cell includes at least one of a serving cell, a target cell, and a candidate cell.

[0014] According to the method performed by the third node provided in the present disclosure, the first information or the fifth information also includes at least one of the following: a cell identifier for indicating a cell associated with the first cell and which does not require a protocol layer reset; a cell identifier for indicating a cell associated with the first cell and which requires a protocol layer reset.

[0015] According to the method performed by the third node provided in the present disclosure, the second information or the fourth information also includes at least one of the following: a cell identifier for indicating a cell associated with the first cell and for which TA measurement is not required; a cell identifier for indicating a cell associated with the first cell and for which TA measurement is required.

[0016] According to the method provided by the present disclosure and executed by the third node, the first message also includes: indication information for indicating the configuration that the third node needs to retain or release; configuration information associated with synchronization, used by the third node to trigger the first node to obtain the synchronization information of the target cell or candidate cell in advance; configuration information associated with the reference signal, used by the third node to configure the measurement of the reference signal; reference configuration information, used by the third node to generate configuration information of the candidate cell; indication information for indicating whether the third node needs to perform a protocol layer reset, and indication information for indicating whether the first node needs to perform TA measurement; configuration information of the source cell, including the configuration information of the first node in the source cell; first default configuration information, including configuration information used by the third node when it is unable to determine whether a protocol layer reset is required.

[0017] According to the method performed by the third node provided in the present disclosure, determining whether to perform a protocol layer reset based on a first message includes at least one of the following: in the case where a cell accessed by the first node changes, determining whether to perform a protocol layer reset based on information related to the protocol layer reset operation of the first node associated with the serving cell, and information related to the protocol layer reset operation of the first node associated with the candidate cell; in the case where a cell accessed by the first node changes, determining whether to perform a protocol layer reset based on information related to the protocol layer reset operation of the first node associated with the target cell, and information related to the protocol layer reset operation of the first node associated with the candidate cell; in the case where a cell accessed by the first node changes, determining whether to perform a protocol layer reset based on information related to the protocol layer reset operation of the first node associated with the first candidate cell, and information related to the protocol layer reset operation of the first node associated with the second candidate cell; determining whether to perform a protocol layer reset based on the indication information used to indicate whether the third node needs to perform a protocol layer reset; determining whether to perform a protocol layer reset based on the cell identifier included in the first information.

[0018] According to the method performed by the third node provided in the present disclosure, determining whether the first node performs TA measurement based on the first message includes at least one of the following: in the case where the cell accessed by the first node changes, determining whether the first node performs TA measurement according to information related to the measurement behavior of the first node associated with the serving cell and information related to the measurement behavior of the first node associated with the candidate cell; in the case where the cell accessed by the first node changes, determining whether the first node performs TA measurement according to information related to the measurement behavior of the first node associated with the target cell and information related to the measurement behavior of the first node associated with the candidate cell; in the case where the cell accessed by the first node changes, determining whether the first node performs TA measurement according to information related to the measurement behavior of the first node associated with the first candidate cell and information related to the measurement behavior of the first node associated with the second candidate cell; determining whether the first node performs TA measurement according to the indication information used to indicate whether the first node needs to perform TA measurement; determining whether the first node performs TA measurement according to the cell identifier included in the second information.

[0019] According to one aspect of the present disclosure, a method performed by a first node is provided, the method comprising: receiving a second message from a second node, the second message comprising third information related to a protocol layer reset and / or fourth information related to a timing advance TA measurement; based on the second message, determining whether the first node performs a protocol layer reset and / or determines whether to perform a timing advance TA measurement; wherein the third information is used to determine a protocol layer reset operation associated with a first cell; wherein the fourth information is used to determine a measurement behavior associated with the first cell; wherein the first cell comprises at least one of a serving cell, a target cell and a candidate cell.

[0020] According to the method performed by the first node provided in the present disclosure, the third information also includes at least one of the following: a cell identifier for indicating a cell associated with the first cell and which does not require a protocol layer reset; a cell identifier for indicating a cell associated with the first cell and which requires a protocol layer reset.

[0021] According to the method performed by the first node provided in the present disclosure, the fourth information also includes at least one of the following: a cell identifier for indicating a cell associated with the first cell and for which TA measurement is not required; a cell identifier for indicating a cell associated with the first cell and for which TA measurement is required.

[0022] According to the method performed by the first node provided in the present disclosure, the second message also includes at least one of the following: information for indicating the configuration that the first node needs to retain or release; second default configuration information, including configuration information used by the first node when it is unable to determine whether a protocol layer reset is required; configuration information of layer 1 / layer 2 triggered mobility LTM, including configuration information of LTM candidate cells.

[0023] According to the method performed by the first node provided by the present disclosure, the protocol layer reset includes: when the first node is an integrated access and backhaul node, resetting the radio link control layer corresponding to the backhaul radio link control channel

[0024] According to another aspect of the present disclosure, a first node is provided, comprising: a transceiver configured to send and / or receive signals to the outside; and a controller configured to control the transceiver to execute the method executed by the first node.

[0025] According to another aspect of the present disclosure, a second node is provided, comprising: a transceiver configured to send and / or receive signals to the outside; and a controller configured to control the transceiver to execute the method executed by the second node.

[0026] According to another aspect of the present disclosure, a third node is provided, comprising: a transceiver configured to send and / or receive signals to the outside; and a controller configured to control the transceiver to execute the method executed by the third node.

[0027] According to another aspect of the present disclosure, a non-transitory computer-readable recording medium is provided, on which a program for executing any of the above methods when executed by a computer is stored. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is an exemplary system architecture for System Architecture Evolution (SAE).

[0029] Figure 2 is an exemplary system architecture according to various embodiments of the present disclosure.

[0030] Figure 3 This is a schematic diagram of interaction among a first node, a second node, and a third node according to an embodiment of the present disclosure.

[0031] Figure 4 is a block diagram showing the structure of a first node according to an embodiment of the present disclosure.

[0032] Figure 5 is a block diagram showing the structure of a second node according to an embodiment of the present disclosure.

[0033] Figure 6 is a block diagram showing the structure of a third node according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. This description includes various specific details to facilitate understanding but should be considered as exemplary only. Therefore, one of ordinary skill in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, for the sake of clarity and conciseness, descriptions of well-known functions and structures may be omitted.

[0035] The terms and expressions used in the following specification and claims are not limited to their dictionary meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purposes only and not for the purpose of limiting the present disclosure as defined in the appended claims and their equivalents.

[0036] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0037] The term "include" or "may include" refers to the presence of the corresponding disclosed functions, operations or components that can be used in various embodiments of the present disclosure, rather than limiting the presence of one or more additional functions, operations or features. In addition, the term "include" or "have" may be interpreted as indicating certain characteristics, numbers, steps, operations, constituent elements, components or combinations thereof, but should not be interpreted as excluding the possibility of the presence of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

[0038] The term "or" used in various embodiments of the present disclosure includes any of the listed terms and all combinations thereof. For example, "A or B" may include A, may include B, or may include both A and B.

[0039] Unless defined differently, all terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as understood by those skilled in the art described in the present disclosure. Common terms as defined in dictionaries are interpreted as having meanings consistent with the context in the relevant technical field, and should not be interpreted ideally or overly formally unless clearly defined in the present disclosure.

[0040] The following discussion Figures 1 to 6The various embodiments used to describe the principles of the present disclosure in this patent document are for illustration only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0041] Figure 1 It is an exemplary system architecture 100 of System Architecture Evolution (SAE). User Equipment (UE) 101 is a terminal device used to receive data. Evolved Universal Terrestrial Radio Access Network (E-UTRAN) 102 is a radio access network, which includes a macro base station (eNodeB / NodeB) that provides a wireless network interface for the UE to access. The Mobility Management Entity (MME) 103 is responsible for managing the mobility context, session context and security information of the UE. The Serving Gateway (SGW) 104 mainly provides user plane functions, and the MME 103 and SGW 104 may be in the same physical entity. The Packet Data Network Gateway (PGW) 105 is responsible for functions such as billing and lawful interception, and may also be in the same physical entity as the SGW 104. The Policy and Charging Rules Function Entity (PCRF) 106 provides Quality of Service (QoS) policies and charging criteria. The General Packet Radio Service Support Node (SGSN) 108 is a network node device that provides routing for data transmission in the Universal Mobile Telecommunications System (UMTS). The Home Subscriber Server (HSS) 109 is the home subsystem of the UE and is responsible for protecting user information including the current location of the user equipment, the address of the service node, user security information, and the packet data context of the user equipment.

[0042] Figure 2 is an exemplary system architecture 200 according to various embodiments of the present disclosure. Other embodiments of the system architecture 200 can be used without departing from the scope of the present disclosure.

[0043] User equipment (UE) 201 is a terminal device used to receive data. The next generation radio access network (NG-RAN) 202 is a radio access network, which includes a base station (gNB or eNB connected to the 5G core network 5GC, the eNB connected to the 5GC is also called ng-gNB) that provides the UE with an access wireless network interface. The access control and mobility management function entity (AMF) 203 is responsible for managing the mobility context and security information of the UE. The user plane function entity (UPF) 204 mainly provides user plane functions. The session management function entity SMF 205 is responsible for session management. The data network (DN) 206 includes services such as operators, Internet access, and third-party services.

[0044] The text and drawings are provided as examples only to help understand the present disclosure. They should not be interpreted as limiting the scope of the present disclosure in any way. Although certain embodiments and examples have been provided, it will be apparent to those skilled in the art based on what is disclosed herein that the embodiments and examples shown may be changed without departing from the scope of the present disclosure.

[0045] Before introducing the specific contents, some assumptions and definitions of the present invention are given below.

[0046] ■The message names in the present invention are only examples, and other message names may also be used.

[0047] ■ The "first" and "second" contained in the message names of the present invention are only examples of messages and do not represent the execution order

[0048] ■ In the present invention, detailed descriptions of steps not related to the present invention are omitted.

[0049] ■ In the present invention, the steps in each process can be executed in combination with each other or individually. The execution steps of each process are only examples and do not exclude other possible execution orders.

[0050] ■In the present invention, the base station can be a 6G base station, a 5G base station (such as gNB, ng-eNB), a 4G base station (such as eNB), or other types of access nodes.

[0051] ■ In the present invention, when the cell accessed by the user equipment changes from one cell to another cell, this behavior can be called handover or cell switch. In the following description, handover and cell switch have the same meaning.

[0052] ■In the present invention, user, user terminal, and user terminal device are equivalent.

[0053] ■In the present invention, the synchronization information may include at least one of the following information:

[0054] Downlink synchronization information;

[0055] Uplink synchronization information, such as timing advance information.

[0056] Nodes involved in the present invention:

[0057] ■First node: User equipment (UE), which can be a mobile phone or the mobile terminal part (IAB-MT) of an IAB node in an Integrated Access & Backhaul (IAB) network;

[0058] ■ Second node: a centralized unit of a base station, or a control plane part of a centralized unit of a base station or a base station;

[0059] ■The third node: a distribution unit of the base station, which may be a distribution unit where a source cell is located during the movement of a user terminal, or a distribution unit where a target cell is located, or a distribution unit where a candidate target cell for switching is located. The source cell or the target cell is a special cell (SpCell, special cell). In one example, the special cell may be a special cell of a master cell group (SpCell of a master cell group) or a primary cell (PCell, Primary cell). In another example, the special cell may be a special cell of a secondary cell group or a primary secondary cell (PSCell: source primary secondary cell group cell).

[0060] The base station involved in the second / third node may be one of the following types (other types that can be used for user terminal access are not excluded):

[0061] ■LTE base station

[0062] 5G base stations

[0063] 6G base stations

[0064] ■NTN Base Station

[0065] ■HAPS base station

[0066] ■Drone Base Station

[0067] ■WIFI access point

[0068] Reset related operations (or protocol layer reset related operations)

[0069] In the present invention, a node (such as a first node, a second node, or a third node) performs a reset-related behavior, which includes "layer 2 reset" (or protocol layer reset) or "layer 2 non-reset" (or protocol layer non-reset). In an example, "layer 2 reset" and "layer 2 non-reset" respectively include the following behaviors:

[0070] ■ Layer 2 reset (L2 reset) may include at least one of the following possible actions:

[0071] ■Re-establish RLC entity. In one example, the RLC entity is the RLC entity corresponding to the configured logical channel; in another example, the RLC entity is the RLC entity corresponding to the backhaul logical channel of the backhaul RLC channel configured for the IAB-MT;

[0072] ■Reset MAC entity (Reset MAC entity);

[0073] ■PDCP entity re-establishment. In one example, the PDCP entity is the PDCP entity corresponding to the configured bearer.

[0074] ■PDCP entity data recovery (PDCP Data Recovery), in an example, the PDCP entity is the PDCP entity corresponding to the configured bearer.

[0075] ■No L2 reset may include at least one of the following possible actions:

[0076] ■Continue to use the current RLC entity. In one example, the RLC entity is the RLC entity corresponding to the configured logical channel; in another example, the RLC entity is the RLC entity corresponding to the backhaul logical channel of the backhaul RLC channel configured for the IAB-MT;

[0077] ■Continue to use the current MAC entity;

[0078] ■Continue to use the current PDCP entity, which in one example is the PDCP entity corresponding to the configured bearer.

[0079] The above-mentioned "layer 2 reset" or "layer 2 non-reset" behavior can be executed by the user terminal (first node), or by the base station or the centralized unit of the base station (second node), or by the distributed unit of the base station (third node). Before executing "layer 2 reset" or "layer 2 non-reset", the above-mentioned nodes need to determine whether to perform layer 2 reset. In one example, when the user terminal (first node) performs cell switching (such as LTM cell change), the first node / second node / third node needs to determine whether to perform layer 2 reset. In another example, after the user terminal (first node) selects a new cell (such as selecting a new cell after a failure occurs and performing an LTM cell change in the new cell), the first node / second node / third node needs to determine whether to perform layer 2 reset.

[0080] ■The step numbers used in describing the embodiments of the present disclosure do not represent the order in which the steps are executed. The following steps can be executed individually or in combination with each other.

[0081] In a mobile network, user equipment will switch between different cells. The main problem caused by switching is that the user equipment will experience communication interruption during this process. The main reason for the interruption is that the user equipment needs to perform measurements for a long time. Before switching, the network side needs to perform signaling interaction between different nodes to determine the target cell and the configuration of the target cell, and then send a switching command to the user equipment. After that, the user equipment also needs to synchronize uplink and downlink with the network side. In this process, the time required for the user equipment to change cells is relatively long, which in turn affects the performance of the user during the mobile process.

[0082] Whether a layer 2 reset is required and / or whether a time advance measurement required for uplink synchronization is required are factors that affect the delay when the user equipment is switched. When switching, the user terminal needs to determine whether a layer 2 reset is required, or whether the time advance measurement required for uplink synchronization can be performed. However, in the actual execution of the switching process, the network side (for example, the distribution unit of the base station) cannot know whether the user terminal needs to be reset or whether the time advance measurement can be performed. This situation will cause the network side and the user terminal side to use different configurations for data transmission, resulting in data transmission errors or waste of resources.

[0083] Various embodiments of the present disclosure propose a method executed by a second node in a communication system, the method comprising: sending a first message to a third node, the first message comprising first information related to a reset of the first node and / or second information related to a timing advance TA measurement of the first node, sending a second message to the first node, the second message comprising third information related to a reset of the first node and / or fourth information related to a timing advance TA measurement of the first node; wherein the first information or the third information comprises reset indication information for indicating information related to a reset operation of the first node associated with a serving cell and / or a target cell and / or a candidate cell; wherein the second information or the fourth information comprises TA indication information for indicating information related to a measurement behavior of the first node associated with a serving cell and / or a target cell and / or a candidate cell.

[0084] In the embodiments provided in the present disclosure, operations related to the reset of the user terminal or information related to TA measurement are determined through signaling interaction between network nodes and between network nodes and user terminals and through acquisition of cell change information of the user terminal. For example, a first message is sent to a third node (for example, a distributed unit of a base station) through a second node (for example, a centralized unit of a base station), and a second message is sent to a first node (for example, a user terminal), wherein the first message or the second message includes information related to the reset of the first node and / or information related to the timing advance TA measurement of the first node, so that the third node and the first node can determine whether to reset and / or determine whether to perform TA measurement based on the first message and the second message, respectively, so that the network side (for example, a distributed unit of a base station) and the user terminal side adopt the same configuration (for example, layer 2 configuration, configuration for the user terminal to perform TA measurement) for data transmission, thereby further avoiding or improving data transmission errors or reducing resource waste.

[0085] In the embodiments provided in the present disclosure, the user terminal may perform timing advance (TA) measurement, such as UE-based TA measurement. Specifically, before the user terminal accesses the target cell, it may obtain the timing advance required for accessing the target cell through measurement. After obtaining this information, the user terminal may avoid performing a random access procedure when accessing the target cell, thereby reducing the delay or communication interruption of the user terminal accessing the target cell.

[0086] In addition, in order to reduce the delay or communication interruption of the user terminal during the switching process, a cell switching method based on layer 1 / layer 2 signaling is proposed, namely L1 / L2 triggered mobility (LTM). Specifically, during the LTM cell change process, the network side triggers the user terminal to switch through layer 1 or layer 2 signaling (such as MAC CE). Furthermore, before triggering the user terminal to switch, the user terminal can also obtain the time advance information required to access the target cell in advance, such as through the user terminal's measurement, or sending a random access signal in advance.

[0087] The following will be combined Figure 3 , various embodiments of the present disclosure are described in detail. Figure 3 , Figure 3 It is a schematic diagram of a first node, a second node, and a third node interacting according to an embodiment of the present disclosure. The embodiment of the present disclosure may include at least one of steps 1-1 to 1-3, and the execution order of each step is not limited. In the embodiment of the present disclosure, it can be ensured that during the LTM cell change process, the network side and the user terminal side can use the same configuration information (such as layer 2 configuration, user terminal TA measurement configuration).

[0088] Step 1-1: The second node sends a first configuration request message (for example, it may also be referred to as a first message, and the present disclosure does not impose any restrictions on the name of the message) to the third node. The message is used to configure the cell of the first node (user terminal), and the cell may be the current service cell of the first node, or the target cell of the handover, or the candidate cell of the handover (such as LTM). After receiving the message, the third node will generate relevant configurations of the cell to help configure the first node. In addition, the third node will determine its own behavior (such as layer 2 reset, triggering the first node to obtain the time advance in advance, triggering the first node to perform early uplink synchronization, etc.) according to the message and the cell changes of the first node. The message may include at least one of the following information:

[0089] ■The first configuration request information of the service cell, which is used to provide the third node with configuration information about the current service cell of the first node. In one example, the service cell is a candidate cell of LTM, and in another example, the service cell is not a candidate cell of LTM.

[0090] The information includes at least one of the following:

[0091] ■First reset-related configuration information, which is used to help the third node determine the reset-related operations that the third node needs to perform when the cell of the first node changes (such as an LTM cell change, or a new cell is selected to perform LTM). Further, the reset-related operations are used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node. The information may include at least one of the following information:

[0092] ◆The first indication information (or first reset indication information) that identifies that the serving cell is not reset, such as Serving Cell No Reset ID, which indicates information about the reset operation associated with the current serving cell. In one example, the information is used to determine whether a layer 2 reset is required when the first node triggers or executes a cell change (such as an LTM cell change) process for a candidate cell (such as an LTM candidate cell) (such as a third node triggering or executing the process, or the first node triggering or executing the process on a selected cell). After receiving the information, the third node will determine whether a reset operation (such as whether to perform a layer 2 reset) is required based on the cell change of the first node (such as from a serving cell to another cell, or from another cell to a serving cell, in one example, the other cell is a candidate cell of LTM) and the indication information. Furthermore, the reset-related operation is used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node, so the information can also be named Intra-DUL2 reset configuration (DU inner layer 2 reset configuration). If the third node receives the information, it will decide to reset the layer 2 (such as the reestablishment of the RLC entity) according to the information during the cell change or handover process within the DU. The beneficial effect of the information is to help the third node know whether the first node has performed a layer 2 reset, and determine whether it needs to perform a layer 2 reset, so as to achieve the same behavior as the first node, and reduce the delay of the cell change of the first node when no layer 2 reset is performed.

[0093] ◆The first cell identification information without reset, the cell indicated by the information is a cell for which the first node does not need to perform a layer 2 reset when a cell change occurs. In one embodiment, the cell is a candidate cell for LTM. In one example, if the cell of the first node is changed from the cell indicated by the "first cell identification information without reset" to the current service cell, the third node does not need to perform a layer 2 reset; in another example, if the cell of the first node is changed from the current service cell to the cell indicated by the "first cell identification information without reset", the third node does not need to perform a layer 2 reset. Further, the reset-related operation is used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node, so the cell indicated by the "first cell identification information without reset" belongs to the same third node as the current service cell. If the third node receives the information, it will decide on the layer 2 reset (such as the reconstruction of the RLC entity) according to the information during the cell change or handover within the DU.

[0094] ◆The first cell identification information to be reset, the cell indicated by the information is the cell for which the first node needs to perform a layer 2 reset when a cell change occurs. In one embodiment, the cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "first cell identification information to be reset" to the current service cell, the third node needs to perform a layer 2 reset; in another example, if the cell of the first node changes from the current service cell to the cell indicated by the "first cell identification information to be reset", the third node needs to perform a layer 2 reset.

[0095] ■Configuration information related to the first TA measurement. In one example, the configuration information is used to instruct the UE to perform timing advance measurement, such as UE-based TA measurement, which can help the user terminal obtain the uplink timing advance of the cell. The purpose of this information is to help the third node determine whether the first node can perform timing advance measurement when the cell of the first node changes (such as an LTM cell change, or a new cell is selected to perform LTM), and thus can help the third node decide whether it is necessary to trigger the first node to perform early TA acquisition (such as Early UL synchronization, such as triggering the first node to send a random access signal to a candidate cell). The information includes at least one of the following information:

[0096] ◆The first indication information (or first TA measurement indication information) identifying the TA measurement of the serving cell, such as ServingCell UE-Measured TA ID, which indicates the measurement behavior of the first node related to the current serving cell (such as performing a measurement of the timing advance based on the user terminal). In one example, the information is used to determine whether it is necessary to perform a measurement of the timing advance based on the user terminal when or before the first node triggers or executes a process of cell change (such as LTM cell change) for a candidate cell (such as an LTM candidate cell) (such as a third node triggering or executing the process, or the first node triggering or executing the process on the selected cell). After receiving the information, the third section will determine whether the first node performs a measurement of the timing advance based on the user terminal based on the cell change of the first node (such as changing from a serving cell to another cell, or from another cell to a serving cell. In one example, the other cell is a candidate cell for LTM) and the indication information. Further, it can be determined whether the third node triggers the first node to obtain the timing advance in advance. The beneficial effect of this information is to help the third node know whether the first node has performed a time advance measurement based on the user terminal, thereby optimizing resource allocation and avoiding unnecessary triggering of early acquisition of time advance (or early uplink synchronization).

[0097] ◆The first cell identification information without TA measurement, the cell indicated by the information is a cell in which the first node does not perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "first cell identification information without TA measurement" to the current service cell, the first node does not perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the current service cell to the cell indicated by the "first cell identification information without TA measurement", the first node does not perform timing advance measurement based on the user terminal.

[0098] ◆The first cell identification information that requires TA measurement, the cell indicated by this information is the cell where the first node needs to perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "first cell identification information that requires TA measurement" to the current service cell, the first node needs to perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the current service cell to the cell indicated by the "first cell identification information that requires TA measurement", the first node needs to perform timing advance measurement based on the user terminal.

[0099] ■The first configuration request information of the target cell, which is used to provide the information of the target cell to the third node so that the third node can generate the configuration of the target cell, and then help the first node to switch the cell. In one example, the target cell is the target cell selected when performing a layer 3 switch (such as the switch is performed after the user terminal receives the RRC switch command sent by the network side, and the RRC switch command is an RRC RRCReconfiguration message containing a reconfiguration information element (ReconfigurationWithSyncIE, information element) with synchronization information). In one example, the target cell is a candidate cell for LTM, and in another example, the target cell is not a candidate cell for LTM. The information includes at least one of the following information:

[0100] ■Target cell identification information, such as Cell ID, NR CGI, PCI, etc.

[0101] ■Second reset-related configuration information, which is used to help the third node determine the reset-related operations that the third node needs to perform after accessing the target cell when the cell of the first node changes (such as an LTM cell change, or a new cell is selected to perform LTM). Further, the reset-related operations are used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node. The information includes at least one of the following information:

[0102] ◆The second indication information (or second reset indication information) indicating that the serving cell is not reset, such as Serving Cell No Reset ID, which indicates information about the reset operation associated with the cell indicated by the above-mentioned "identification information of the target cell". In one example, the information is used to determine whether a layer 2 reset is required when the first node triggers or executes a cell change (such as an LTM cell change) process for a candidate cell (such as an LTM candidate cell) (such as a third node triggers or executes the process, or the first node triggers or executes the process on a selected cell). After receiving the information, the third node will determine whether a reset operation is required (such as whether to perform a layer 2 reset) based on the cell change of the first node (such as changing from the cell indicated by the above-mentioned "identification information of the target cell" to other cells, or from other cells to the cell indicated by the above-mentioned "identification information of the target cell", in one example, the other cell is a candidate cell of LTM) and the indication information. Furthermore, the reset-related operations are used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node, so the information can also be named Intra-DU L2 reset configuration. If the third node receives this information, it will decide on the layer 2 reset (such as the reconstruction of the RLC entity) based on the information during the cell change or handover within the DU. The beneficial effect of this information is to help the third node know whether the first node has performed a layer 2 reset, achieve the same behavior as the first node, and determine whether it needs to perform a layer 2 reset, and reduce the delay of the first node cell change when no layer 2 reset is performed.

[0103] ◆The second cell identification information without reset, the cell indicated by the information is a cell for which the first node does not need to perform layer 2 reset when a cell change occurs. In one embodiment, the cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "second cell identification information without reset" to the cell indicated by the above-mentioned "identification information of the target cell", the third node does not need to perform layer 2 reset; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "second cell identification information without reset", the third node does not need to perform layer 2 reset. Further, the reset-related operation is used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node, so the cell indicated by the "second cell identification information without reset" belongs to the third node. If the third node receives the information, it will decide on layer 2 reset (such as reconstruction of RLC entity) according to the information during the cell change or handover within the DU.

[0104] ◆The second cell identification information to be reset, the cell indicated by this information is the cell that the first node needs to perform layer 2 reset when a cell change occurs. In one embodiment, this cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "second cell identification information to be reset" to the cell indicated by the above-mentioned "identification information of the target cell", the third node needs to perform layer 2 reset; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "second cell identification information to be reset", the third node needs to perform layer 2 reset.

[0105] ■Configuration information related to the second TA measurement. In one example, the configuration information is used to instruct the UE to perform timing advance measurement, such as UE-based TA measurement, which can help the user terminal obtain the uplink timing advance of the cell. The purpose of this information is to help the third node determine whether the first node can perform timing advance measurement when the cell of the first node changes (such as an LTM cell change or a new cell is selected to perform LTM) after the first node accesses the target cell, and thus can help the third node decide whether it is necessary to trigger the first node to perform early TA acquisition (such as Early UL synchronization, such as triggering the first node to send a random access signal to the candidate cell). The information includes at least one of the following information:

[0106] ◆The second indication information (or second TA measurement indication information) identifying the TA measurement of the serving cell, such as ServingCell UE-Measured TA ID, which indicates the measurement behavior of the first node related to the cell indicated by the above-mentioned "identification information of the target cell" (such as performing the measurement of the timing advance based on the user terminal). In one example, the information is used to determine whether it is necessary to perform the measurement of the timing advance based on the user terminal when or before the first node triggers or executes the process of cell change (such as LTM cell change) for a candidate cell (such as LTM candidate cell) (such as the third node triggers or executes the process, or the first node triggers or executes the process on the selected cell). After receiving the information, the third node will determine whether the first node performs the measurement of the timing advance based on the user terminal according to the cell change of the first node (such as changing from the cell indicated by the above-mentioned "identification information of the target cell" to other cells, or from other cells to the cell indicated by the above-mentioned "identification information of the target cell", in one example, the other cell is a candidate cell of LTM) and the indication information. Further, it can be determined whether the third node triggers the first node to obtain the timing advance in advance. The beneficial effect of this information is to help the third node know whether the first node has performed a time advance measurement based on the user terminal, thereby optimizing resource allocation and avoiding unnecessary triggering of early acquisition of time advance (or early uplink synchronization).

[0107] ◆The second cell identification information without TA measurement, the cell indicated by the information is a cell in which the first node does not perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "second cell identification information without TA measurement" to the cell indicated by the above-mentioned "identification information of the target cell", the first node does not perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "second cell identification information without TA measurement", the first node does not perform timing advance measurement based on the user terminal.

[0108] ◆The second cell identification information that requires TA measurement, the cell indicated by this information is the cell where the first node needs to perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "second cell identification information that requires TA measurement" to the cell indicated by the above-mentioned "identification information of the target cell", the first node needs to perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "second cell identification information that requires TA measurement", the first node needs to perform timing advance measurement based on the user terminal.

[0109] ■The first configuration retention indication information indicates the configuration that the third node needs to retain. In one example, the configuration that the third node needs to retain is the configuration about LTM (LTM-config), in another example, the configuration that the third node needs to retain is the configuration of the source cell, and in another example, the configuration that the third node needs to retain is the configuration about LTM in the configuration of the source cell. In one embodiment, the configuration that needs to be retained indicated by the information is the configuration used in the source cell, and further, these configurations that need to be retained may be the information contained in the following "configuration information of the source cell". The information includes at least one of the following information:

[0110] ◆First indication information of the reserved configuration, which indicates the configuration that the third node needs to retain. In one example, for LTM, the information indicates that the third node needs to retain the configuration of LTM (such as the configuration of LTM included in the “configuration information of the source cell” described below, LTM-config). Further, the information also includes at least one of the following information:

[0111] ● The identification information of the reserved configuration. In one example, for LTM, the information is the identification information of the candidate configuration of LTM, which indicates an LTM candidate configuration.

[0112] ● The identification information of the cell corresponding to the reserved configuration. In one example, for LTM, this information is the identification information of the LTM candidate cell.

[0113] ◆First indication information of the released configuration, which indicates the configuration to be released, and includes at least one of the following information:

[0114] Identification information of the released configuration. In one example, for LTM, this information is identification information of the candidate configuration of LTM, which indicates an LTM candidate configuration.

[0115] · Identification information of the cell corresponding to the released configuration. In one example, for

[0116] LTM, this information is the identification information of the LTM candidate cell

[0117] ■The first configuration information of the candidate cell, which is a candidate cell prepared by the second node for the first node for switching. In one example, the switching may be a layer 3 switching, and in another example, the switching is an LTM cell change. In one example, the first configuration information of the candidate cell is provided to the third node (the third node is the node serving the target cell of the layer 3 switching) when configuring the layer 3 switching; in another example, the first configuration information of the candidate cell is provided to the third node when reconfiguring the serving cell of the current first node; in another example, the first configuration information of the candidate cell is provided to the third node when configuring other candidate cells (such as preparing other candidate cells). The information contains configuration information of one or more candidate cells. For a candidate cell, the information includes at least one of the following information:

[0118] ■Candidate cell identification information, such as Cell ID, NR CGI, PCI, etc.

[0119] ■Third reset-related configuration information, which is used to help the third node determine the reset-related operations that the third node needs to perform when the cell of the first node changes (such as an LTM cell change, or a new cell is selected to perform LTM). In one embodiment, the reset-related operations are used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node. Furthermore, when the above-mentioned "identification information of the candidate cell" belongs to the third node, this information may be included to indicate the reset-related operations. The information includes at least one of the following information:

[0120] ◆ The third indication information (or third reset indication information) indicating no reset, such as No Reset ID, indicates information about the reset operation associated with the cell indicated by the above-mentioned "identification information of the candidate cell". In one example, the information is used to determine whether a layer 2 reset is required when the first node is triggered or executes a cell change (such as an LTM cell change) process for a candidate cell (or an LTM candidate cell) (such as a third node triggering or executing the process, or the first node triggering or executing the process on a selected cell). After receiving the information, the third node will determine whether a reset operation is required (such as whether to perform a layer 2 reset) based on the cell change of the first node (such as changing from the cell indicated by the above-mentioned "identification information of the candidate cell" to other cells, or from other cells to the cell indicated by the above-mentioned "identification information of the candidate cell", in one example, the other cell is a candidate cell of the LTM, and in another example, the other cell is not a candidate cell of the LTM) and the indication information. Furthermore, the reset-related operations are used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node, so the information can also be named Intra-DU L2 reset configuration. If the third node receives this information, it will decide on the layer 2 reset (such as the reconstruction of the RLC entity) based on the information during the cell change or handover within the DU. The beneficial effect of this information is to help the third node know whether the first node has performed a layer 2 reset, and determine whether it needs to perform a layer 2 reset, thereby achieving the same behavior as the first node, and reducing the delay of the first node's cell change when no layer 2 reset is performed.

[0121] ◆ The third cell identification information without reset, the cell indicated by the information is a cell for which the first node does not need to perform layer 2 reset when a cell change occurs. In one embodiment, the cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "third cell identification information without reset" to the cell indicated by the above "identification information of the candidate cell", the third node does not need to perform layer 2 reset; in another example, if the cell of the first node changes from the cell indicated by the above "identification information of the candidate cell" to the cell indicated by the "third cell identification information without reset", the third node does not need to perform layer 2 reset. Further, the reset-related operation is used when a cell change (Intra-DU cell switch) or handover (Intra-DU handover) occurs within the third node, so the cell indicated by the "third cell identification information without reset" belongs to the third node. If the third node receives the information, it will decide on layer 2 reset (such as reconstruction of RLC entity) according to the information during the cell change or handover within the DU.

[0122] ◆The third cell identification information that needs to be reset. The cell indicated by the information is the cell that needs to be reset at layer 2 when the first node changes. In one embodiment, the cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "third cell identification information that needs to be reset" to the cell indicated by the above "candidate cell identification information", the third node needs to perform a layer 2 reset; in another example, if the cell of the first node changes from the cell indicated by the above "candidate cell identification information" to the cell indicated by the "third cell identification information that needs to be reset", the third node needs to perform a layer 2 reset.

[0123] ■ Configuration information related to the third TA measurement. In one example, the configuration information is used to instruct the UE to perform timing advance measurement, such as UE-based TA measurement, which can help the user terminal obtain the uplink timing advance of the cell. The purpose of this information is to help the third node determine whether the first node can perform timing advance measurement when the cell of the first node changes (such as an LTM cell change, or a new cell is selected to perform LTM), and thus can help the third node decide whether it is necessary to trigger the first node to perform early TA acquisition (such as Early UL synchronization, such as triggering the first node to send a random access signal to a candidate cell). The information includes at least one of the following information:

[0124] ◆The third indication information (or third TA measurement indication information) for identifying TA measurement, such as UE-Measured TA ID, indicating the measurement behavior of the first node related to the cell indicated by the above "identification information of candidate cells" (such as performing measurement of timing advance based on user terminals). In one example, the information is used to determine whether the first node needs to perform measurement of timing advance based on user terminals when or before the first node triggers or executes a process of cell change (such as LTM cell change) for a candidate cell (such as LTM candidate cell) (such as the third node triggers or executes the process, or the first node triggers or executes the process on the selected cell). After receiving the information, the third node will determine whether the first node performs measurement of timing advance based on the user terminal according to the cell change of the first node (such as changing from the cell indicated by the above "identification information of candidate cells" to other cells, or from other cells to the cell indicated by the above "identification information of candidate cells", in one example, the other cell is a candidate cell of LTM, and in another example, the other cell is not a candidate cell of LTM) and the indication information, and further, it can be determined whether the third node triggers the first node to obtain the timing advance in advance. The beneficial effect of this information is to help the third node know whether the first node has performed a time advance measurement based on the user terminal, thereby optimizing resource allocation and avoiding unnecessary triggering of early acquisition of time advance (or early uplink synchronization).

[0125] ◆The third cell identification information without TA measurement, the cell indicated by this information is a cell for which the first node does not perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "third cell identification information without TA measurement" to the cell indicated by the above-mentioned "identification information of the candidate cell", the first node does not perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the candidate cell" to the cell indicated by the "third cell identification information without TA measurement", the first node does not perform timing advance measurement based on the user terminal.

[0126] ◆The third cell identification information that requires TA measurement, the cell indicated by this information is the cell where the first node needs to perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "third cell identification information that requires TA measurement" to the cell indicated by the above-mentioned "identification information of the candidate cell", the first node needs to perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the candidate cell" to the cell indicated by the "third cell identification information that requires TA measurement", the first node needs to perform timing advance measurement based on the user terminal.

[0127] ■ Synchronization configuration information. In one example, the information is used by the third node to trigger the user terminal to obtain synchronization information (such as timing advance information) of the target cell or the candidate cell in advance, such as triggering the user terminal to send a random access signal to the target cell or the candidate cell. The information includes at least one of the following information:

[0128] ◆ RACH configuration required for early synchronization, or RACH-less RACH configuration, or Early UL synchronization configuration, which is used by the first node to obtain synchronization information of the target cell or candidate cell (or send a random access signal to the target cell or candidate cell) before receiving a handover command (such as a command for triggering a user to change an LTM cell, LTM MAC Control Element), and includes at least one of the following information:

[0129] ● Frequency domain indication information, which indicates the frequency domain information of the random access signal (such as the random access pilot signal preamble) sent by the first node, such as the frequency of the common uplink carrier, the frequency of the supplementary uplink carrier, and the configuration information of the bandwidth part (BWP) (such as BWP ID, BWP range, etc.)

[0130] Sequence-related information, which indicates the sequence used to send the random access signal, such as prach-RootSequenceIndex

[0131] Time alignment timer, which indicates the effective time of the time advance, such as time advance timer

[0132] RACH generic configuration, which indicates the generic configuration information for sending random access signals, including at least one of the following information: prach-configurationIndex random access channel configuration index information, target power of the network receiver side receiving preamble (preamble) preambleReceivedTargetPower, maximum number of preamble transmissions premableTransMax, increase step size of the preamble transmission power powerRampingSetp, size of the random access response window ra-ResponseWindow, etc.

[0133] RACH dedicated configuration, which indicates dedicated configuration information for sending random access signals. This information may vary for different users and includes at least one of the following information: RACH occasion information (which indicates the resources for sending random access signals), the number of SSBs corresponding to each RACHoccasion ssb-perRACH-occassion, resource configuration information (such as the mask index for random access resource selection physical random access

[0134] channel mask index), corresponding to the SSB or CSI-RS index SSB / CSIRS-

[0135] index, the index of the preamble code ra-PreambleIndex

[0136] ◆Configuration information related to contention free random access, or configuration information of RACH-based RACH, which is used by the first node to obtain the synchronization information of the target cell or candidate cell (or send a random access signal to the target cell or candidate cell) when receiving a handover command (such as a command for triggering the user to change the LTM cell, LTM MAC Control Element). In an example, when the first node receives a handover command (such as a command for triggering the user to change the LTM cell), the first node will send a random access signal according to the information in the handover command, and then obtain the synchronization information of the target cell or candidate cell (such as the timing advance). The handover command may include at least one of the following information: such as the preamble index, the indication information of the uplink carrier (such as indicating supplementary UL or indicating normal UL, etc.), SSB (Synchronization signal block) index information, physical random access channel mask index Physical random access channel mask index, etc. The information includes at least one of the following information:

[0137] Frequency domain indication information

[0138] Information about the sequence

[0139] Time alignment timer

[0140] RACH generic configuration

[0141] RACH dedicated configuration

[0142] For a detailed description of the above information, please refer to the description of each information in the above “RACH configuration required for early synchronization”.

[0143] ◆Beam configuration information, which indicates the beam used by the first node when sending a signal (such as a random access signal). The information includes at least one of the following information:

[0144] ● Downlink beam indication information, such as transmission configuration indication

[0145] Configuration indication (TCI) state index

[0146] Uplink beam indication information, such as TCI status index

[0147] ●Indication information of uplink and downlink beams, such as TCI status index

[0148] ■Reference signal configuration information, which can be used by the third node to configure the measurement of the reference signal, thereby helping the first node to measure the candidate cell. In one example, the reference signal can be a CSI-RS signal, such as CSI resource configuration information. In another example, the reference signal can be a downlink synchronization signal (such as SSB), such as SSB configuration information. The information includes at least one of the following information:

[0149] ◆First signal configuration identification information, which identifies a set of configurations of the signal measured by the first node

[0150] ◆First resource information, which indicates the resource used by the measured signal, and may include at least one of the following information:

[0151] ●First frequency domain resource information, which indicates the position of the frequency domain where the signal is located. In one embodiment, the position can be indicated by a frequency point. In one embodiment, the position can be indicated by a frequency point and a bandwidth. In another embodiment, the position can be indicated by an identifier of a frequency domain resource, such as an identifier of a range of frequency domain resources. In another embodiment, the position can be indicated by an identifier of a frequency band, such as an identifier of a bandwidth part BWP (bandwidth part) or an identifier of a sub-band. In another embodiment, the frequency domain resource can be given by configuration information of the BWP. Further, the user equipment should be able to measure signals of non-serving cells (such as synchronization signal blocks SSB) within the configured BWP.

[0152] Subcarrier spacing information

[0153] First time domain resource information, which indicates the time domain location of the signal. To indicate the location, the information may include at least one of the following information:

[0154] ■ Cycle

[0155] ■Offset

[0156] ■Time unit number (such as time slot number, symbol number)

[0157] ■Time Length

[0158] ■Start time, which indicates the time when the signal measurement starts

[0159] ■SSB position indication information, such as SSB position in burst

[0160] ◆Configuration information of the synchronization signal block measurement timing configuration SMTC (SSB Measurement Timing Configuration), which gives the configuration information of the cell's SSB, such as period, offset, measurement duration, indication information of the physical cell identity PCI (Physical cell identity), SSB location information, etc.

[0161] ■ Reference configuration information, which is used by the third node to generate configuration information of the candidate cell. In one embodiment, the configuration information of the candidate cell is a differential configuration (Delta configuration) generated based on the reference configuration information. The configuration information includes at least one of the configuration information of the bearer, the configuration information of the SDAP, the configuration information of the PDCP, the configuration information of the RLC, the configuration information of the MAC, and the configuration information of the physical layer; in one example, the configuration information includes the content of the RRC Reconfiguration message, and in another example, the configuration information includes the content in the Cell group configuration (CellgroupConfig).

[0162] ■The first indication information of reset (or first reset information), which indicates whether to perform reset, such as indicating to perform the above-mentioned "layer 2 reset", such as indicating to perform the above-mentioned "layer 2 non-reset". After the third node receives the information, the third node performs layer 2 reset or does not perform layer 2 reset according to the indication information; in one example, before step 1-1, the second node learns the cell to be accessed by the first node (such as notifying the second node through the third node), and then the second node determines the "first indication information of reset" according to the cell to be accessed by the first node;

[0163] ■The first indication information of TA measurement (or the first TA measurement information), which indicates the measurement behavior of the first node (such as performing the measurement of the timing advance based on the user terminal), such as the first node needs to perform the measurement of the timing advance based on the user terminal. After receiving the information, the third node determines whether the first node performs the measurement of the timing advance based on the user terminal. In one example, if the first node performs the measurement of the timing advance based on the user terminal, the third node will not configure the first node to obtain the timing advance. In one example, before step 1-1, the second node learns the cell that the first node is going to access (such as informing the second node through the third node), and then the second node determines the "first indication information of TA measurement" based on the cell that the first node is accessing;

[0164] ■Configuration information of the source cell, which includes configuration information of the user terminal (first node) in the source cell, such as bearer configuration information, SDAP / PDCP / RLC / MAC / PHY configuration information. Further, the information may also include LTM configuration information (LTM-Config) in the source cell.

[0165] ■Default layer 2 configuration information, which is the configuration information used by the third node when it is not possible to determine whether layer 2 reset is required (such as when the first node sends the first RRC message to the third node), and the configuration information can be used for data transmission with the first node. The information includes at least one of the following configuration information: RLC layer configuration information, logical channel configuration information, MAC layer configuration information, and physical layer configuration information.

[0166] After receiving the first configuration request message, the third node will determine its own behavior according to the cell change subsequently performed by the first node, such as determining whether to perform a layer 2 reset, or determining whether the first node performs a time advance measurement based on the user terminal, and then determining whether the third node triggers the first node to obtain the time advance in advance or initiate uplink synchronization. The cell change of the first node may be implemented in different ways:

[0167] ■Implementation method 1: The cell of the first node is changed by triggering the LTM cell change process, such as switching from cell 1 to cell 2. Cell 1 may be a candidate cell for LTM or not, and cell 2 is a candidate cell for LTM. When cell 1 is not a candidate cell for LTM, in one example, cell 1 is the current serving cell, and in another example, cell 1 is the target cell for switching (such as the target cell for L3 switching). In this implementation method, the third node can determine whether the cell of the first node has changed according to whether the third node has sent a command to change the cell to the first node.

[0168] ■Implementation method 2: A new cell is selected through the cell selection process, which causes the cell of the first node to change. Further, the first node will perform the LTM cell change process in the selected cell. In one example, the cell selection performed by the first node is because the first node has a link failure (such as a wireless link failure, a handover failure, a reconfiguration failure, etc.). For example, the new cell selected by the first node is cell 2, and the cell accessed by the first node before the cell selection (such as the cell accessed before the link failure) is cell 1. This cell 1 may be a candidate cell for LTM, or it may not be a candidate cell for LTM, and cell 2 is a candidate cell for LTM. When cell 1 is not a candidate cell for LTM, in one example, cell 1 is the current serving cell, and in another example, cell 1 is the target cell for switching (such as the target cell for L3 switching). In this implementation method, the third node can determine whether the first node has a cell change based on the information received by the third node from the first node (such as the identifier of the cell selected by the first node, the identifier of the source cell where the first node is located when switching or LTM cell change, the random access signal sent by the first node, etc.).

[0169] The way the third node determines whether to perform a layer 2 reset:

[0170] When the cell of the first node changes (for example, according to the above implementation mode, the cell changes from cell 1 to cell 2. In one embodiment, the cell change is determined by the third node), the third node determines whether to perform layer 2 reset according to at least one of the following methods based on the above “first indication information indicating that the serving cell is not reset” or “second indication information indicating that the serving cell is not reset” or “third indication information indicating that the serving cell is not reset” (or a variable maintained by the third node, such as variable information indicating that the serving cell is not reset, which is stored at the third node):

[0171] ■Method 1: When the cell change of the first node is from the current service cell (cell 1) to one of the candidate cells (cell 2), it is determined based on the above-mentioned "first indication information indicating that the service cell is not reset" of the service cell (cell 1) and the above-mentioned "third indication information indicating that the service cell is not reset" of the candidate cell (cell 2). When the above-mentioned "first indication information indicating that the service cell is not reset" (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) of the service cell is the same (equal) as the above-mentioned "third indication information indicating that the service cell is not reset" of the candidate cell, Layer 2 reset is not performed, such as executing the above-mentioned "Layer 2 not reset" behavior; when the above-mentioned "first indication information indicating that the service cell is not reset" (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) of the service cell is different (not equal) from the above-mentioned "third indication information indicating that the service cell is not reset" of the candidate cell, Layer 2 reset is performed, such as executing the above-mentioned "Layer 2 reset" behavior. Further, after the first node accesses cell 2, cell 2 becomes a new service cell, thereby updating the above-mentioned "first indication information indicating that the service cell is not reset" (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) of the service cell to the above-mentioned "third indication information indicating that the service cell is not reset" of cell 2, so as to determine whether to perform Layer 2 reset in the subsequent cell change process of the first node.

[0172] ■Method 2: After the first node accesses the target cell in the switching process, when the cell change of the first node is from the target cell (cell 1) to one of the candidate cells (cell 2), it is determined based on the above-mentioned "second indication information indicating that the service cell is not reset" of the target cell (cell 1) (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) and the above-mentioned "third indication information indicating that the service cell is not reset" of the candidate cell (cell 2). When the above-mentioned "second indication information indicating that the service cell is not reset" (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) of the target cell is the same (equal) as the above-mentioned "third indication information indicating that the service cell is not reset" of the candidate cell, Layer 2 reset is not performed, such as executing the above-mentioned "Layer 2 not reset" behavior; when the above-mentioned "second indication information indicating that the service cell is not reset" (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) of the target cell is different (not equal) from the above-mentioned "third indication information indicating that the service cell is not reset" of the candidate cell, Layer 2 reset is performed, such as executing the above-mentioned "Layer 2 reset" behavior. Further, after the first node accesses cell 2, cell 2 becomes a new service cell, thereby updating the above-mentioned "first indication information indicating that the service cell is not reset" (or a variable maintained by the third node, such as variable information indicating that the service cell is not reset) of the service cell to the above-mentioned "third indication information indicating that the service cell is not reset" of cell 2, so as to determine whether to perform Layer 2 reset in the subsequent cell change process of the first node.

[0173] ■Method three: When the cell change of the first node is from one candidate cell (cell 1) to another candidate cell (cell 2), it is determined based on the above-mentioned "third indication information that the identifier is not reset" of cell 1 (or a variable maintained by the third node, such as variable information that the identifier service cell is not reset) and the above-mentioned "third indication information that the identifier is not reset" of cell 2. When the above-mentioned "third indication information that the identifier is not reset" (or a variable maintained by the third node, such as variable information that the identifier is not reset for the service cell) of cell 1 is the same (equal) as the above-mentioned "third indication information that the identifier is not reset" of cell 2, layer 2 reset is not performed, such as executing the above-mentioned "layer 2 reset" behavior; when the above-mentioned "third indication information that the identifier is not reset" (or a variable maintained by the third node, such as variable information that the identifier is not reset for the service cell) of cell 1 is different (not equal) from the above-mentioned "third indication information that the identifier is not reset" of cell 2, layer 2 reset is performed, such as executing the above-mentioned "layer 2 reset" behavior. Further, after the first node accesses cell 2, cell 2 becomes a new service cell, thereby updating the above-mentioned "first indication information that the identifier is not reset for the service cell" (or a variable maintained by the third node, such as variable information that the identifier is not reset for the service cell) of the service cell to the above-mentioned "third indication information that the identifier is not reset" of cell 2, so as to determine whether to perform layer 2 reset in the subsequent cell change process of the first node.

[0174] ■ Mode 4: The third node is directly determined according to the above “first indication information of reset” contained in the first configuration request message. For the specific method, please refer to the above description of “first indication information of reset”.

[0175] ■Method 5: Determine based on the above-mentioned “first cell identification information without reset” or “second cell identification information without reset” or “third cell identification information without reset” or “first cell identification information to be reset” or “second cell identification information to be reset” or “third cell identification information to be reset” contained in the first configuration request message. For specific methods, please refer to the above description of the above identification information.

[0176] ■Method 6: The first node directly informs the third node whether to reset layer 2 through signaling.

[0177] The third node determines the manner in which the first node performs measurement of the timing advance based on the user terminal:

[0178] When the cell of the first node changes (for example, according to the above implementation mode, the cell changes from cell 1 to cell 2. In one embodiment, the cell change is determined by the third node), the third node determines that the first node performs the measurement of the timing advance based on the user terminal according to at least one of the following methods according to the above “first indication information identifying the TA measurement of the serving cell” or “second indication information identifying the TA measurement of the serving cell” or “third indication information identifying the TA measurement” (or a variable maintained by the third node, such as variable information identifying the TA measurement, which is stored at the third node):

[0179] ■Method 1: When the cell change of the first node is from the current service cell (cell 1) to one of the candidate cells (cell 2), it is determined based on the above-mentioned "first indication information identifying TA measurement of the service cell" of the service cell (cell 1) (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) and the above-mentioned "third indication information identifying TA measurement" of the candidate cell (cell 2). When the above-mentioned "first indication information identifying TA measurement of the serving cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the serving cell is the same (equal) as the above-mentioned "third indication information identifying TA measurement" of the candidate cell, the first node performs timing advance measurement based on the user terminal; when the above-mentioned "first indication information identifying TA measurement of the serving cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the serving cell is different (not equal) from the above-mentioned "third indication information identifying TA measurement" of the candidate cell, the first node does not perform timing advance measurement based on the user terminal. Further, after the first node accesses cell 2, cell 2 becomes a new serving cell, thereby updating the above-mentioned "first indication information identifying TA measurement of the serving cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the serving cell to the above-mentioned "third indication information identifying TA measurement" of cell 2, so as to determine whether the first node performs timing advance measurement based on the user terminal during the subsequent cell change process of the first node.

[0180] ■Method 2: After the first node accesses the target cell in the switching process, when the cell change of the first node is from the target cell (cell 1) to one of the candidate cells (cell 2), it is determined based on the above-mentioned "second indication information identifying TA measurement of the service cell" of the target cell (cell 1) (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) and the above-mentioned "third indication information identifying TA measurement" of the candidate cell (cell 2). When the above-mentioned "second indication information identifying TA measurement of the serving cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the target cell is the same (equal) as the above-mentioned "third indication information identifying TA measurement" of the candidate cell, the first node performs timing advance measurement based on the user terminal; when the above-mentioned "second indication information identifying TA measurement of the serving cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the target cell is different (not equal) from the above-mentioned "third indication information identifying TA measurement" of the candidate cell, the first node does not perform timing advance measurement based on the user terminal. Further, after the first node accesses cell 2, cell 2 becomes a new serving cell, thereby updating the above-mentioned "first indication information identifying TA measurement of the serving cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the serving cell to the above-mentioned "third indication information identifying TA measurement" of cell 2, so as to determine whether the first node performs timing advance measurement based on the user terminal during the subsequent cell change process of the first node.

[0181] ■Method three: When the cell change of the first node is from one candidate cell (cell 1) to another candidate cell (cell 2), it is determined based on the above-mentioned "third indication information identifying TA measurement" of cell 1 (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) and the above-mentioned "third indication information identifying TA measurement" of cell 2. When the above-mentioned "third indication information identifying TA measurement" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of cell 1 is the same (equal) as the above-mentioned "third indication information identifying TA measurement" of cell 2, the first node performs timing advance measurement based on the user terminal; when the above-mentioned "third indication information identifying TA measurement" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of cell 1 is different (not equal) from the above-mentioned "third indication information identifying TA measurement" of cell 2, the first node does not perform timing advance measurement based on the user terminal. Further, after the first node accesses cell 2, cell 2 becomes a new service cell, thereby updating the above-mentioned "first indication information identifying TA measurement of the service cell" (or a variable maintained by the third node, such as variable information identifying TA measurement, which is stored at the third node) of the service cell to the above-mentioned "third indication information identifying TA measurement" of cell 2, so as to determine whether the first node performs timing advance measurement based on the user terminal during the subsequent cell change process of the first node.

[0182] ■ Mode 4: The third node determines directly according to the above “first indication information of TA measurement” contained in the first configuration request message. For the specific method, please refer to the above description of “first indication information of TA measurement”.

[0183] ■Method 5: Determine based on the above-mentioned “first cell identification information without TA measurement” or “second cell identification information without TA measurement” or “third cell identification information without TA measurement” or “first cell identification information requiring TA measurement” or “second cell identification information requiring TA measurement” or “third cell identification information requiring TA measurement” contained in the first configuration request message. For specific methods, please refer to the above description of the above-mentioned identification information.

[0184] ■ Mode 6: The first node directly informs the third node through signaling whether to perform timing advance measurement based on the user terminal.

[0185] Step 1-2: The third node sends a first configuration response message (for example, also referred to as a third message, and the present disclosure does not impose any restriction on the name of the message) to the second node, where the message includes at least one of the following information:

[0186] ■First configuration response information of the serving cell, which includes at least one of the following information:

[0187] ■ Configuration information of the serving cell, such as the configuration information of the cell group, CellGroupConfig, which includes at least one of the following configurations of the serving cell: bearer configuration information, RLC configuration information, MAC layer configuration information, physical layer configuration information, and measurement configuration information

[0188] ■Fourth reset related configuration information, which includes at least one of the following information:

[0189] ◆ The fourth indication information indicating that the serving cell is not reset (or the fourth reset indication information), see the description of the above-mentioned “the first indication information indicating that the serving cell is not reset”

[0190] ◆ The fourth cell identification information without reset, see the description of "the first cell identification information without reset" above

[0191] ◆ The fourth cell identification information to be reset, see the description of the above “first cell identification information to be reset”

[0192] After receiving the above information, the second node will determine whether the third node needs to perform a reset operation (such as whether to reset layer 2) based on the cell change of the first node (such as from a service cell to other cells, or from other cells to a service cell. In one example, the other cell is a candidate cell for LTM) and the above information. For specific methods, please refer to the descriptions in the above methods one to six for determining whether to reset layer 2.

[0193] ■Fourth TA measurement related configuration information, which includes at least one of the following information:

[0194] ◆ The fourth indication information (or fourth TA measurement indication information) for identifying the TA measurement of the serving cell, see the description of the above “the first indication information for identifying the TA measurement of the serving cell”

[0195] ◆ The fourth cell identification information without TA measurement, see the description of "the first cell identification information without TA measurement" above

[0196] ◆ The fourth cell identification information that needs to be measured by the TA, see the description of the above “the first cell identification information that needs to be measured by the TA”

[0197] After receiving the above information, the second node determines whether the first node needs to perform a measurement of the timing advance based on the user terminal according to the cell change of the first node (such as changing from a serving cell to another cell, or from another cell to a serving cell. In one example, the other cell is a candidate cell for LTM) and the above information. For specific methods, refer to the description of the above methods 1 to 6 for determining to perform a measurement of the timing advance based on the user terminal.

[0198] In an example, the above-mentioned "fourth reset-related configuration information" (or "fourth TA measurement-related configuration information") and the above-mentioned "first reset-related configuration information" (or "first TA measurement-related configuration information") will not appear in the above-mentioned first configuration request message and the first configuration response message respectively at the same time. If it is decided by the second node, only the "first reset-related configuration information" (or "first TA measurement-related configuration information") will be included in the first configuration request message; if it is decided by the third node, only the "fourth reset-related configuration information" (or "fourth TA measurement-related configuration information") will be included in the first configuration response message.

[0199] ■First configuration response information of the target cell, which includes at least one of the following information:

[0200] ■Configuration information of the target cell, such as the configuration information of the cell group, CellGroupConfig, which includes at least one of the following configurations of the target cell: bearer configuration information, RLC configuration information, MAC layer configuration information, physical layer configuration information, and measurement configuration information

[0201] ■Fifth reset related configuration information, which includes at least one of the following information:

[0202] ◆ The fifth indication information indicating that the serving cell is not reset (or the fifth reset indication information), see the description of the above “the second indication information indicating that the serving cell is not reset”

[0203] ◆ The fifth cell identification information without reset, see the description of "the second cell identification information without reset" above

[0204] ◆ The fifth cell identification information to be reset, see the description of the above “second cell identification information to be reset”

[0205] After receiving the above information, the second node will determine whether the third node needs to perform a reset operation (such as whether to reset layer 2) based on the cell change of the first node (such as from a service cell to other cells, or from other cells to a service cell. In one example, the other cell is a candidate cell for LTM) and the above information. For specific methods, please refer to the descriptions in the above methods one to six for determining whether to reset layer 2.

[0206] ■Fifth TA measurement related configuration information, which includes at least one of the following information:

[0207] ◆ The fifth indication information for identifying the TA measurement of the serving cell (or the fifth TA measurement indication information), see the description of the above “the second indication information for identifying the TA measurement of the serving cell”

[0208] ◆ The fifth cell identification information without TA measurement, see the description of "the second cell identification information without TA measurement" above

[0209] ◆ The fifth cell identification information that needs to be measured by the TA, see the description of the above “Second cell identification information that needs to be measured by the TA”

[0210] After receiving the above information, the second node determines whether the first node needs to perform a measurement of the timing advance based on the user terminal according to the cell change of the first node (such as changing from a serving cell to another cell, or from another cell to a serving cell. In one example, the other cell is a candidate cell for LTM) and the above information. For specific methods, refer to the description of the above methods 1 to 6 for determining to perform a measurement of the timing advance based on the user terminal.

[0211] In an example, the above-mentioned "fifth reset-related configuration information" (or "fifth TA measurement-related configuration information") and the above-mentioned "second reset-related configuration information" (or "second TA measurement-related configuration information") will not appear in the above-mentioned first configuration request message and the first configuration response message respectively at the same time. If it is decided by the second node, only the "second reset-related configuration information" (or "second TA measurement-related configuration information") will be included in the first configuration request message; if it is decided by the third node, only the "fifth reset-related configuration information" (or "fifth TA measurement-related configuration information") will be included in the first configuration response message.

[0212] ■First configuration response information of the candidate cell, which includes at least one of the following information:

[0213] ■Sixth reset related configuration information, which includes at least one of the following information:

[0214] ◆ The sixth indication information indicating that the mark is not reset (or the sixth reset indication information), see the description of the above “the third indication information indicating that the mark is not reset”

[0215] ◆ For the sixth cell identification information that is not reset, please refer to the description of "the third cell identification information that is not reset" above

[0216] ◆ The sixth cell identification information to be reset, see the description of the above “third cell identification information to be reset”

[0217] After receiving the above information, the second node will determine whether the third node needs to perform a reset operation (such as whether to reset layer 2) based on the cell change of the first node (such as from a service cell to other cells, or from other cells to a service cell. In one example, the other cell is a candidate cell for LTM) and the above information. For specific methods, please refer to the descriptions in the above methods one to six for determining whether to reset layer 2.

[0218] ■ Sixth TA measurement related configuration information, the information includes at least one of the following information:

[0219] ◆ The sixth indication information for identifying TA measurement (or the sixth TA measurement indication information), see the description of the above “the third indication information for identifying TA measurement”

[0220] ◆ The sixth cell identification information without TA measurement, see the description of "the third cell identification information without TA measurement" above

[0221] ◆ The sixth cell identification information that needs to be measured by the TA, see the description of the above “the third cell identification information that needs to be measured by the TA”

[0222] After receiving the above information, the second node determines whether the first node needs to perform a measurement of the timing advance based on the user terminal according to the cell change of the first node (such as changing from a serving cell to another cell, or from another cell to a serving cell. In one example, the other cell is a candidate cell for LTM) and the above information. For specific methods, refer to the description of the above methods 1 to 6 for determining to perform a measurement of the timing advance based on the user terminal.

[0223] In an example, the above-mentioned "sixth reset-related configuration information" (or "sixth TA measurement-related configuration information") and the above-mentioned "third reset-related configuration information" (or "third TA measurement-related configuration information") will not appear in the above-mentioned first configuration request message and the first configuration response message respectively at the same time. If decided by the second node, only the "third reset-related configuration information" (or "third TA measurement-related configuration information") will be included in the first configuration request message; if decided by the third node, only the "sixth reset-related configuration information" (or "sixth TA measurement-related configuration information") will be included in the first configuration response message.

[0224] ■Default layer 2 configuration information, which is the configuration information used by the first node when it is not possible to determine whether layer 2 reset is required (such as when the first node sends the first RRC message to the third node), and the configuration information can be used for data transmission between the third node and the first node. The information includes at least one of the following configuration information: RLC layer configuration information, logical channel configuration information, MAC layer configuration information, and physical layer configuration information.

[0225] Step 1-3: The second node sends a first configuration message (for example, also referred to as a second message, the present disclosure does not impose any restrictions on the name of the message) to the first node, and the message is used to provide the user terminal with configuration information related to the cell handover. In one example, the cell handover may be a layer 3 handover, and in another example, the cell handover is an LTM. The message includes at least one of the following information:

[0226] ■ The second configuration information of the target cell. In one example, the target cell is the target cell selected when performing a layer 3 handover (e.g., the handover is performed after the user terminal receives an RRC handover command sent by the network side, and the RRC handover command is an RRC RRCReconfiguration message containing a ReconfigurationWithSync IE, such as the first configuration message is the RRC handover command). The information includes at least one of the following information:

[0227] ■Target cell identification information

[0228] ■The seventh reset-related configuration information, which is used to help the first node determine the reset-related operations that the first node needs to perform when the cell of the first node changes after accessing the target cell indicated by the above-mentioned "identification information of the target cell". In an example, when the above-mentioned first configuration message is a message used to trigger a layer 3 handover (such as an RRC Reconfiguration message containing a ReconfigurationWithSync IE, such as a handover command message), and / or the variables of the first node (such as a variable storing an LTM candidate configuration, LTM-config variable) contain at least one LTM candidate configuration, then the above-mentioned first configuration message may contain the "seventh reset-related configuration information" or the following "seventh indication information indicating that the serving cell is not reset". The information includes at least one of the following information:

[0229] ◆The seventh indication information (or the seventh reset indication information) indicating that the serving cell is not reset, such as Serving Cell No Reset ID, which indicates the information of the reset operation associated with the cell indicated by the above-mentioned "identification information of the target cell". In one example, the information is used to determine whether a layer 2 reset is required when the first node is triggered or executes a cell change (such as an LTM cell change) process for a candidate cell (such as an LTM candidate cell) (such as a third node triggering or executing the process, or the first node triggering or executing the process on a selected cell). After receiving the information, the third node will determine whether a reset operation (such as whether to perform a layer 2 reset) is required based on the cell change of the first node (such as changing from the cell indicated by the above-mentioned "identification information of the target cell" to other cells, or from other cells to the cell indicated by the above-mentioned "identification information of the target cell", in one example, the other cell is a candidate cell of LTM) and the indication information. The beneficial effect of this information is to help the first node know whether to perform a layer 2 reset and reduce the delay of the first node cell change when the layer 2 reset is not performed. In an example, after receiving the information, the first node may maintain second variable information indicating that the serving cell is not reset, and may update the variable with the “seventh indication information indicating that the serving cell is not reset”.

[0230] ◆ The seventh cell identification information without reset, the cell indicated by the information is a cell for which the first node does not need to perform a layer 2 reset when a cell change occurs. In one embodiment, the cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "seventh cell identification information without reset" to the cell indicated by the above-mentioned "identification information of the target cell", the third node does not need to perform a layer 2 reset; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "seventh cell identification information without reset", the third node does not need to perform a layer 2 reset.

[0231] ◆The seventh cell identification information that needs to be reset. The cell indicated by this information is the cell that needs to be reset at layer 2 when the first node changes. In one embodiment, this cell is a candidate cell for LTM. In one example, if the cell of the first node changes from the cell indicated by the "seventh cell identification information that needs to be reset" to the cell indicated by the above-mentioned "identification information of the target cell", the third node needs to perform a layer 2 reset; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "seventh cell identification information that needs to be reset", the third node needs to perform a layer 2 reset.

[0232] ■ The seventh TA measurement-related configuration information, in one example, is used to instruct the UE to perform timing advance measurement, such as UE-based TA measurement. The purpose of this information is to help the first node determine whether the first node can perform timing advance measurement when the cell of the first node changes (such as an LTM cell change occurs, or a new cell is selected to perform LTM) after accessing the target cell, and further help the third node decide whether it is necessary to trigger the first node to perform early TA acquisition (such as Early UL synchronization, such as triggering the first node to send a random access signal to the candidate cell). In one example, when the above-mentioned first configuration message is a message for triggering layer 3 handover (such as an RRC Reconfiguration message containing ReconfigurationWithSyncIE, such as a handover command message), and / or the variable of the first node (such as a variable storing LTM candidate configuration, LTM-config variable) contains at least one LTM candidate configuration, the above-mentioned first configuration message may include the "seventh measurement-related configuration information" or the following "seventh indication information identifying TA measurement of the serving cell". The information includes at least one of the following information:

[0233] ◆The seventh indication information (or the seventh TA measurement indication information) for identifying the TA measurement of the serving cell, such as ServingCell UE-Measured TA ID, which indicates the measurement behavior of the first node related to the cell indicated by the above-mentioned "identification information of the target cell" (such as performing a measurement of the timing advance based on the user terminal). In one example, the information is used to determine whether it is necessary to perform a measurement of the timing advance based on the user terminal when or before the first node triggers or executes a process of cell change (such as LTM cell change) for a candidate cell (such as an LTM candidate cell) (such as a third node triggering or executing the process, or the first node triggering or executing the process on a selected cell). After receiving the information, the first node will determine whether the first node performs a measurement of the timing advance based on the user terminal according to the cell change of the first node (such as changing from the cell indicated by the above-mentioned "identification information of the target cell" to other cells, or from other cells to the cell indicated by the above-mentioned "identification information of the target cell", in one example, the other cell is a candidate cell of LTM) and the indication information. The first node may maintain a second variable information identifying the TA measurement, which may be updated with the "seventh indication information identifying the TA measurement of the serving cell". The beneficial effect of this information is to help the first node determine whether the measurement based on the timing advance of the user terminal is performed, thereby reducing the interruption delay during the switching process.

[0234] ◆The seventh cell identification information without TA measurement, the cell indicated by this information is a cell for which the first node does not perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "seventh cell identification information without TA measurement" to the cell indicated by the above-mentioned "identification information of the target cell", the first node does not perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "seventh cell identification information without TA measurement", the first node does not perform timing advance measurement based on the user terminal.

[0235] ◆The seventh cell identification information that requires TA measurement, the cell indicated by this information is the cell where the first node needs to perform timing advance measurement based on the user terminal when a cell change occurs. In one example, if the cell of the first node changes from the cell indicated by the "seventh cell identification information that requires TA measurement" to the cell indicated by the above-mentioned "identification information of the target cell", the first node needs to perform timing advance measurement based on the user terminal; in another example, if the cell of the first node changes from the cell indicated by the above-mentioned "identification information of the target cell" to the cell indicated by the "seventh cell identification information that requires TA measurement", the first node needs to perform timing advance measurement based on the user terminal.

[0236] ■Second configuration retention indication information, which indicates the configuration that the first node needs to retain. In one example, the configuration that the first node needs to retain is the configuration about LTM (LTM-config). In another example, the configuration that the first node needs to retain is the configuration of the source cell. In another example, the configuration that the first node needs to retain is the configuration about LTM in the configuration of the source cell. The information includes at least one of the following information:

[0237] ◆Second indication information of retaining configuration, the information indicates the configuration that the first node needs to retain. In one example, for LTM, the information indicates that the first node needs to retain the configuration of LTM (such as the configuration of LTM included in the above-mentioned “configuration information of the source cell”, LTM-config). Further, the information also includes at least one of the following information:

[0238] ● The identification information of the reserved configuration. In one example, for LTM, the information is the identification information of the candidate configuration of LTM, which indicates an LTM candidate configuration.

[0239] ● The identification information of the reserved cell. In one example, for LTM, this information is the identification information of the LTM candidate cell.

[0240] ◆Second indication information of the released configuration, which indicates the configuration to be released, and includes at least one of the following information:

[0241] ●Identification information of the released configuration. In one example, for LTM, this information is identification information of the candidate configuration of LTM, which indicates an LTM candidate configuration.

[0242] ● Identification information of the released cell. In one example, for LTM, this information is the identification information of the LTM candidate cell. ■ Default layer 2 configuration information. This information is the configuration information used by the first node when it is unable to determine whether a layer 2 reset is required (such as when the first node sends the first RRC message to the third node). This configuration information can be used by the first node to perform data transmission with the third node. This information includes at least one of the following configuration information: configuration information of the RLC layer, configuration information of the logical channel, configuration information of the MAC layer, and configuration information of the physical layer.

[0243] ■LTM configuration information, which includes the configuration information of LTM candidate cells, such as the information contained in the RRCReconfiguration message of the candidate cells.

[0244] In the above process, the first configuration request message may be a user context setup request message (UE ContextSetup Request) or a user context modification request message (UE Context Modification Request); the first configuration response message may be a user context setup response message (UE Context Setup Response) or a user context modification response message (UE Context Modification Response); the first configuration message may be an RRC reconfiguration message. The above message may also be other messages.

[0245] In the above-mentioned embodiments provided in the present disclosure, operations related to the reset of the user terminal or information related to TA measurement are determined through signaling interaction between network nodes and between network nodes and user terminals and through acquisition of cell change information of the user terminal, so that the network side (for example, it can be a distribution unit of a base station) and the user terminal side use the same configuration (for example, layer 2 configuration, configuration for the user terminal to perform TA measurement) for data transmission, thereby further avoiding or improving data transmission errors, or avoiding waste of resources.

[0246] In the process of the following implementation, the specific description of the information contained in each message can refer to the description in the above steps 1-1 / 1-2 / 1-3.

[0247] Implementation method 1: Configuring the target cell for layer 3 switching (the third node is the distribution unit where the target cell is located)

[0248] In this embodiment, the first node is configured to perform layer 3 handover, and the first node is configured with LTM related configuration information in the source cell. When the first node receives a layer 3 handover command or accesses the target cell, the first node may retain at least part of the LTM configuration information.

[0249] This implementation method includes the following process:

[0250] Step a-1: The second node sends a first configuration request message (such as UE context setup request) to a third node, where the third node is a node serving a target cell. The first configuration request message is used to prepare a target cell of the first node. The first configuration request message may include at least one of the following information:

[0251] ■First configuration request information of the target cell, which includes at least one of the following information:

[0252] ■Target cell identification information

[0253] ■ Second reset related configuration information

[0254] ■Configuration information related to the second TA measurement

[0255] ■First configuration retains the instruction information

[0256] ■First configuration information of a candidate cell, which includes configuration information of one or more candidate cells. For a candidate cell, the information includes at least one of the following information:

[0257] ■Identification information of candidate cells

[0258] ■Third reset related configuration information

[0259] ■ Configuration information related to the third TA measurement

[0260] ■Synchronized configuration information

[0261] ■Reference signal configuration information

[0262] ■Reference configuration information

[0263] ■Configuration information of the source cell

[0264] Step a-2: The third node sends a first configuration response message (such as UE context setupresponse) to the second node. The first configuration response message provides configuration information of the target cell. The information included in the message can be found in the above steps 1-2.

[0265] Step a-3: The second node sends a first configuration message (such as RRCReconfiguration) to the first node. The message may be sent through a third node or through other nodes (such as a distribution unit of a source cell serving the first node). The message is a message for configuring the first node to perform layer 3 handover, such as an RRC Reconfiguration message containing Reconfigurationwith synchronization IE. After receiving the message, the first node will perform layer 3 handover. The message includes the following information, which can be referred to the description in the above steps 1-3. If the first node continues to retain the configuration information of LTM when performing the layer 3 handover, the first configuration message will not indicate the deletion of the LTM configuration information. In an example, in order to ensure that the first node can continue to change the LTM cell, the first configuration message will include the above "seventh reset-related configuration information" and / or the above "seventh indication information indicating that the serving cell is not reset" and / or the above "seventh TA measurement-related configuration information" and / or the above "seventh indication information indicating TA measurement of the serving cell". Further, after receiving this information, the first node will use this information to update the corresponding variables.

[0266] The beneficial effect of the above process is that after the first node performs layer 3 switching, the configuration information of LTM is still maintained, and the candidate LTM cell can be changed, thereby reducing the delay and communication interruption during the cell change process.

[0267] Implementation method 2: configuring the serving cell or LTM candidate cell of the first node (the third node is the distribution unit where the source cell is located or the distribution unit where the candidate cell is located)

[0268] Example 1: Reset-related configuration and / or TA measurement-related configuration is determined by the CU

[0269] This example includes the following process:

[0270] Step b-1: The second node sends a first configuration request message to a third node, where the third node is a node of a current serving cell serving the first node. The first configuration request message includes at least one of the following information:

[0271] ■First configuration request information of the serving cell, which includes at least one of the following information:

[0272] ■First reset related configuration information

[0273] ■Configuration information related to the first TA measurement

[0274] ■First configuration information of a candidate cell, which includes configuration information of one or more candidate cells. For a candidate cell, the information includes at least one of the following information:

[0275] ■Identification information of candidate cells

[0276] ■Third reset related configuration information

[0277] ■ Configuration information related to the third TA measurement

[0278] ■Synchronized configuration information

[0279] ■Reference signal configuration information

[0280] ■Reference configuration information

[0281] Step b-2: The third node sends a first configuration response message to the second node. The first configuration response message provides configuration information of the target cell. The information included in the message can refer to the above step 1-2.

[0282] Step b-3: The second node sends a first configuration message to the first node, which may be sent through the third node. The message is to reconfigure the current serving cell of the first node, such as an RRCReconfiguration message. Further, the message may also include information on reconfiguring the LTM. The information included in the message can refer to the above steps 1-3.

[0283] When the first node accesses a new cell, the third node determines whether to reset layer 2 or whether the first node performs a measurement of the timing advance based on the user terminal. In one example, the third node determines based on the cell that receives the information of the first node; in another example, the third node determines based on the information sent by the first node to the third node, and the information sent by the third node to the first node includes at least one of the following information: identification information of the source cell (the source cell is the source cell of the LTM cell change, or the cell to which the first node is connected before the cell selection), configuration information related to the reset of the source cell (for details, please refer to the above "configuration information related to the first reset"), configuration information related to the TA measurement of the source cell (for details, please refer to the above "configuration information related to the first TA measurement"), indication information of layer 2 reset (such as indicating whether layer 2 reset is required), and indication information of TA measurement (used to indicate whether the first node performs a measurement of the timing advance based on the user terminal). In another example, the third node will be determined based on the information sent by the second node, such as the "first indication information of reset" and / or the "first indication information of TA measurement" in the above-mentioned first configuration request message. Optionally, the above-mentioned information sent by the second node is determined based on the information received from the first node. The information sent by the first node (in one example, the information is forwarded to the first node by the third node) includes at least one of the following information: identification information of the source cell (the source cell is the source cell of the LTM cell change, or the cell to which the first node is connected before cell selection), configuration information related to the reset of the source cell (for details, please refer to the above-mentioned "first reset-related configuration information"), configuration information related to TA measurement of the source cell (for details, please refer to the above-mentioned "first TA measurement-related configuration information"), indication information of layer 2 reset (such as indicating whether layer 2 reset is required), and indication information of TA measurement (used to indicate whether the first node performs measurement of the timing advance based on the user terminal).

[0284] The beneficial effect of this implementation is that the CU can determine appropriate layer 2 reset parameters and / or TA measurement parameters according to the capabilities of the user terminal and the cell accessed, thereby reducing communication interruption and resource waste during the user terminal cell change process.

[0285] Example 2: Reset-related configuration and / or TA measurement-related configuration is determined by DU

[0286] This example includes the following process:

[0287] Step c-1: The second node sends a first configuration request message to a third node, where the third node is a node serving a current serving cell of the first node. The message does not include configuration information related to reset and / or configuration information related to TA measurement. The first configuration request message includes at least one of the following information:

[0288] ■ First configuration request information of the serving cell

[0289] ■First configuration information of a candidate cell, which includes configuration information of one or more candidate cells. For a candidate cell, the information includes at least one of the following information:

[0290] ■Identification information of candidate cells

[0291] ■Synchronized configuration information

[0292] ■Reference signal configuration information

[0293] ■Reference configuration information

[0294] Step c-2: The third node sends a first configuration response message to the second node. The first configuration response message provides configuration information of the target cell. The information contained in the message can refer to the above step 1-2. The message includes at least one of the following information:

[0295] ■First configuration response information of the serving cell, which includes at least one of the following information:

[0296] ■Configuration information of service cell

[0297] ■Fourth reset related configuration information

[0298] ■ Fourth TA measurement related configuration information

[0299] ■First configuration response information of the target cell, which includes at least one of the following information:

[0300] ■Configuration information of the target cell

[0301] ■ Fifth reset related configuration information

[0302] ■Fifth TA measurement related configuration information

[0303] ■First configuration response information of the candidate cell, which includes at least one of the following information:

[0304] ■Sixth reset related configuration information

[0305] ■6th TA measurement related configuration information

[0306] ■Default layer 2 configuration information

[0307] Step c-3: The second node sends a first configuration message to the first node, which may be sent through the third node. The message is to reconfigure the current serving cell of the first node, such as an RRCReconfiguration message. Further, the message may also include information on reconfiguring the LTM. The information contained in the message can refer to the above steps 1-3.

[0308] The beneficial effect of this implementation is that the DU can determine appropriate layer 2 reset parameters and / or TA measurement parameters based on the capabilities of the user terminal, the cell it accesses, and its own resource conditions, ensuring that parameter configuration consistent with the user terminal is obtained, reducing communication interruption and resource waste during the user terminal cell change process.

[0309] In another embodiment, when the first node is an IAB node, the first node determines whether to reconstruct the RLC entity corresponding to the backhaul RLC channel according to the configuration information related to LTM and the configuration of the first node when performing LTM cell change or L3 handover. Specifically, the second node sends a first configuration message to the first node, and the message includes the configuration information of the target cell of the L3 handover or the configuration information of the LTM candidate cell, for example, at least one of the following information:

[0310] ■ Reset configuration information of the serving cell, which indicates the reset configuration of the serving cell of the first node or the target cell of L3 handover, such as Serving Cell No Reset ID

[0311] ■Candidate cell identification information, which indicates the identification of the LTM candidate cell of the first node; ■Candidate cell reset configuration information, which indicates the reset configuration of the LTM candidate cell of the first node, such as No Reset ID

[0312] When the first node performs a cell change (such as L3 handover or LTM cell change), the first node may perform at least one of the following actions:

[0313] ■Retain the backhaul logical channel identification information of the backhaul RLC channel, as well as the corresponding RLC entities, state variables, buffers, and timers;

[0314] ■ If the target cell of the handover (such as the candidate cell of LTM or the target cell of L3 handover) is not configured with "reset configuration information of the serving cell", and / or the first node does not store "reset configuration information of the serving cell", after the first node performs the handover (performs the configuration of the LTM candidate cell), the RLC entity corresponding to the backhaul logical channel identifier is rebuilt

[0315] ■If the serving cell is configured with "reset configuration information of the serving cell", and the switching target cell (such as the candidate cell of LTM or the target cell of L3 switching) is configured with "reset configuration information of the candidate cell", and the two are different, after the first node executes the switching (executes the configuration of the LTM candidate cell), the RLC entity corresponding to the return logical channel identifier is rebuilt.

[0316] In addition, it can be understood that the contents contained in each message in the above-mentioned embodiments are only examples of the present disclosure. The contents contained in various similar or identical messages can be replaced with each other according to the situation, or named with different names, or some items can be added or deleted. For the sake of brevity, the meanings of similar content items can be explained to each other according to the context without further elaboration. The modified and interpreted implementation methods still fall within the scope of protection of the present invention.

[0317] Figure 4 is a block diagram showing the structure of a first node 400 according to an embodiment of the present disclosure.

[0318] refer to Figure 4 , the first node 400 includes a transceiver 401 and a controller 402. The transceiver 401 is configured to send signals to the outside and receive signals from the outside. The controller 402 is configured to execute the method performed by the first node. The first node 400 can be implemented in the form of hardware, software, or a combination of hardware and software so that it can execute the method performed by the first node described in the present disclosure.

[0319] Figure 5 is a block diagram showing the structure of the second node 500 according to an embodiment of the present disclosure.

[0320] refer to Figure 5 , the second node 500 includes a transceiver 501 and a controller 502. The transceiver 501 is configured to send signals to the outside and receive signals from the outside. The controller 502 is configured to execute the method performed by the second node. The second node 500 can be implemented in the form of hardware, software, or a combination of hardware and software so that it can execute the method performed by the second node described in the present disclosure.

[0321] Figure 6 is a block diagram showing the structure of a third node 600 according to an embodiment of the present disclosure.

[0322] refer to Figure 6, the third node 600 includes a transceiver 601 and a controller 602. The transceiver 601 is configured to send signals to the outside and receive signals from the outside. The controller 602 is configured to execute the method performed by the third node. The third node 600 can be implemented in the form of hardware, software, or a combination of hardware and software so that it can execute the method performed by the third node described in the present disclosure.

[0323] At least one embodiment of the present disclosure also provides a non-transitory computer-readable recording medium having stored thereon a program for executing the above method when executed by a computer.

[0324] Various embodiments of the present disclosure may be implemented as computer-readable codes embodied on a computer-readable recording medium from a specific perspective. A computer-readable recording medium is any data storage device that can store data readable by a computer system. Examples of computer-readable recording media may include read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, optical data storage device, carrier wave (e.g., data transmission via the Internet), and the like. Computer-readable recording media may be distributed via a computer system connected via a network, and therefore computer-readable codes may be stored and executed in a distributed manner. Moreover, the functional programs, codes, and code segments for implementing the various embodiments of the present disclosure may be easily interpreted by a technician in the field of the embodiments of the present disclosure.

[0325] It will be understood that the embodiments of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. The software may be stored as program instructions or computer-readable codes executable on a controller on a non-transient computer-readable medium. Examples of non-transient computer-readable recording media include magnetic storage media (e.g., ROM, floppy disk, hard disk, etc.) and optical recording media (e.g., CD-ROM, digital video disk (DVD), etc.). The non-transient computer-readable recording medium may also be distributed on a network-coupled computer system so that the computer-readable code is stored and executed in a distributed manner. The medium may be read by a computer, stored in a memory, and executed by a controller. Various embodiments may be implemented by a computer or a portable terminal including a controller and a memory, and the memory may be an example of a non-transient computer-readable recording medium suitable for storing (multiple) programs with instructions for implementing the embodiments of the present disclosure. The present disclosure may be implemented by a program having a code for specifically implementing the apparatus and method described in the claims, the program being stored in a machine (or computer) readable storage medium. The program may be electronically carried on any medium, such as a communication signal transmitted via a wired or wireless connection, and the present disclosure suitably includes its equivalents.

[0326] The above description is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can make various changes or substitutions within the technical scope disclosed in the present disclosure, and these changes or substitutions should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method performed by a second node in a communication system, the method comprising: Sending a first message to a third node or receiving a third message from the third node, wherein the first message includes first information related to a protocol layer reset and / or second information related to a timing advance TA measurement, and the third message includes fifth information related to a protocol layer reset and / or sixth information related to a timing advance TA measurement; Sending a second message to the first node, where the second message includes third information related to protocol layer reset and / or fourth information related to timing advance TA measurement; The first information, the third information, or the fifth information is used to determine a protocol layer reset operation associated with the first cell; The second information, the fourth information, or the sixth information is used to determine a measurement behavior associated with the first cell; The first cell includes at least one of a serving cell, a target cell and a candidate cell.

2. The method according to claim 1, wherein: The first information, the third information, or the fifth information further includes at least one of the following: A cell identifier used to indicate a cell associated with the first cell and for which a protocol layer reset is not required; A cell identifier used to indicate a cell associated with the first cell and requiring a protocol layer reset; and / or The second information, the fourth information, or the sixth information further includes at least one of the following: A cell identifier used to indicate a cell associated with the first cell and for which TA measurement is not required; Used to indicate a cell identifier of a cell that is associated with the first cell and for which TA measurement needs to be performed.

3. The method according to claim 1, wherein: The first message further includes at least one of the following: Indication information used to indicate configuration that the third node needs to retain or release; Configuration information associated with synchronization, used by the third node to trigger the first node to obtain synchronization information of the target cell or the candidate cell in advance; Configuration information associated with the reference signal, used for the third node to configure measurement of the reference signal; Reference configuration information, used by the third node to generate configuration information of candidate cells; Indication information used to indicate whether the third node needs to perform a protocol layer reset, Indication information used to indicate whether the first node needs to perform TA measurement; Configuration information of the source cell, including configuration information of the first node in the source cell; The first default configuration information includes configuration information used by the third node when it is not possible to determine whether a protocol layer reset is required.

4. The method according to claim 3, wherein: The configuration information associated with synchronization includes at least one of the following: The first synchronization configuration information includes configuration information related to the first node obtaining synchronization information of the target cell or the candidate cell in advance; The second synchronization configuration information includes configuration information related to the first node acquiring synchronization information of the target cell or the candidate cell through a random access process; Configuration information associated with the beam, used to indicate the beam used by the first node when sending a signal; and / or The configuration information associated with the reference signal includes at least one of the following: First signal configuration identification information, used to identify the configuration of the signal measured by the first node; First resource information, used to indicate resources used by the measured signal; The configuration information of the synchronization signal block measurement timing configuration SMTC is used to indicate the configuration information of the synchronization signal block SSB of the cell.

5. The method according to claim 1, wherein: The second message further includes at least one of the following: Information used to indicate configuration that the first node needs to retain or release; The second default configuration information includes configuration information used by the first node when it is not possible to determine whether a protocol layer reset is required; Configuration information of layer 1 / layer 2 triggered mobility LTM, including configuration information of LTM candidate cells; and / or The third message further includes at least one of the following: The third default configuration information includes configuration information used by the first node when it is not possible to determine whether a protocol layer reset is required.

6. A method performed by a third node in a communication system, the method comprising: receiving a first message from the second node, and determining whether to perform a protocol layer reset and / or determining whether the first node performs TA measurement based on the first message; or Sending a third message to the second node, The first message includes first information related to protocol layer reset and / or second information related to timing advance TA measurement, The third message includes fifth information related to protocol layer reset and / or sixth information related to timing advance TA measurement; The first information or the fifth information is used to determine a protocol layer reset operation associated with the first cell; The second information or the sixth information is used to determine a measurement behavior associated with the first cell; The first cell includes at least one of a serving cell, a target cell and a candidate cell.

7. The method according to claim 6, wherein: The first information or the fifth information also includes at least one of the following: A cell identifier used to indicate a cell associated with the first cell and for which a protocol layer reset is not required; A cell identifier used to indicate a cell associated with the first cell and requiring a protocol layer reset; and / or The second information or the fourth information further includes at least one of the following: A cell identifier used to indicate a cell associated with the first cell and for which TA measurement is not required; Used to indicate a cell identifier of a cell that is associated with the first cell and for which TA measurement needs to be performed.

8. The method according to claim 6, wherein: The first message also includes: Indication information used to indicate configuration that the third node needs to retain or release; Configuration information associated with synchronization, used by the third node to trigger the first node to obtain synchronization information of the target cell or the candidate cell in advance; Configuration information associated with the reference signal, used for the third node to configure measurement of the reference signal; Reference configuration information, used by the third node to generate configuration information of candidate cells; Indication information used to indicate whether the third node needs to perform a protocol layer reset, Indication information used to indicate whether the first node needs to perform TA measurement; Configuration information of the source cell, including configuration information of the first node in the source cell; The first default configuration information includes configuration information used by the third node when it is not possible to determine whether a protocol layer reset is required.

9. The method according to claim 6, wherein: Determining whether to perform a protocol layer reset based on the first message includes at least one of the following: In the case where the cell accessed by the first node changes, determining whether to perform a protocol layer reset according to information related to a protocol layer reset operation for indicating the first node associated with the serving cell and information related to a protocol layer reset operation for indicating the first node associated with the candidate cell; In the case where the cell accessed by the first node changes, determining whether to perform a protocol layer reset according to information related to a protocol layer reset operation for indicating the first node associated with the target cell and information related to a protocol layer reset operation for indicating the first node associated with the candidate cell; In the case where the cell accessed by the first node changes, determining whether to perform a protocol layer reset according to information related to a protocol layer reset operation of the first node associated with the first candidate cell and information related to a protocol layer reset operation of the first node associated with the second candidate cell; Determining whether to perform a protocol layer reset according to the indication information used to indicate whether the third node needs to perform a protocol layer reset; Determining whether to perform a protocol layer reset according to the cell identifier included in the first information; and / or Determining whether the first node performs TA measurement based on the first message includes at least one of the following: In a case where the cell accessed by the first node changes, determining whether the first node performs TA measurement according to information related to the measurement behavior of the first node associated with the serving cell and information related to the measurement behavior of the first node associated with the candidate cell; In a case where the cell accessed by the first node changes, determining whether the first node performs TA measurement according to information related to the measurement behavior of the first node associated with the target cell and information related to the measurement behavior of the first node associated with the candidate cell; In a case where the cell accessed by the first node changes, determining whether the first node performs TA measurement according to information related to the measurement behavior of the first node associated with the first candidate cell and information related to the measurement behavior of the first node associated with the second candidate cell; Determining whether the first node performs TA measurement according to indication information used to indicate whether the first node needs to perform TA measurement; Determine whether the first node performs TA measurement according to the cell identifier included in the second information.

10. A method performed by a first node in a communication system, the method comprising: receiving a second message from the second node, wherein the second message includes third information related to protocol layer reset and / or fourth information related to timing advance TA measurement; Based on the second message, determining whether the first node performs a protocol layer reset and / or determining whether to perform a timing advance TA measurement; The third information is used to determine a protocol layer reset operation associated with the first cell; The fourth information is used to determine a measurement behavior associated with the first cell; The first cell includes at least one of a serving cell, a target cell and a candidate cell.

11. The method according to claim 10, wherein: The third information also includes at least one of the following: A cell identifier used to indicate a cell associated with the first cell and for which a protocol layer reset is not required; Used to indicate a cell identifier of a cell that is associated with the first cell and that requires protocol layer reset.

12. The method according to claim 10, wherein: The fourth information also includes at least one of the following: A cell identifier used to indicate a cell associated with the first cell and for which TA measurement is not required; Used to indicate a cell identifier of a cell that is associated with the first cell and for which TA measurement needs to be performed.

13. The method according to claim 10, wherein: The second message further includes at least one of the following: Information used to indicate configuration that the first node needs to retain or release; The second default configuration information includes configuration information used by the first node when it is not possible to determine whether a protocol layer reset is required; Configuration information of layer 1 / layer 2 triggered mobility LTM, including configuration information of LTM candidate cells.

14. The method of claim 10, wherein the protocol layer reset comprises: When the first node is an integrated access and backhaul node, a radio link control layer corresponding to the backhaul radio link control channel is reset.

15. A node device, comprising: A transceiver configured to transmit and / or receive signals with the outside; as well as A controller is configured to control the transceiver to execute the method according to any one of claims 1-14.

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