Method and apparatus in a wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Various embodiments of the disclosure propose a method performed by a third node in a communication system, the method comprising: receiving a first message from a second node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and transmitting a second message to the second node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node, wherein the first message is used for requesting to prepare a target cell for handover of the first node.

Description

METHOD AND APPARATUS IN A WIRELESS COMMUNICATION SYSTEM

[0001] The disclosure relates to the field of communication, and more specifically, to a method performed by a third node, a method performed by a second node, a method performed by a fifth node, a method performed by a fourth node, a third node, a second node, a fifth node, and a fourth node.

[0002] Considering the development of wireless communication from generation to generation, the technologies have been developed mainly for services targeting humans, such as voice calls, multimedia services, and data services. Following the commercialization of 5G (5th generation) communication systems, it is expected that the number of connected devices will exponentially grow. Increasingly, these will be connected to communication networks. Examples of connected things may include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machines, and factory equipment. Mobile devices are expected to evolve in various form-factors, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (6th generation) era, there have been ongoing efforts to develop improved 6G communication systems. For these reasons, 6G communication systems are referred to as beyond-5G systems.

[0003] 6G communication systems, which are expected to be commercialized around 2030, will have a peak data rate of tera (1,000 giga)-level bit per second (bps) and a radio latency less than 100μsec, and thus will be 50 times as fast as 5G communication systems and have the 1 / 10 radio latency thereof.

[0004] In order to accomplish such a high data rate and an ultra-low latency, it has been considered to implement 6G communication systems in a terahertz (THz) band (for example, 95 gigahertz (GHz) to 3THz bands). It is expected that, due to severer path loss and atmospheric absorption in the terahertz bands than those in mmWave bands introduced in 5G, technologies capable of securing the signal transmission distance (that is, coverage) will become more crucial. It is necessary to develop, as major technologies for securing the coverage, Radio Frequency (RF) elements, antennas, novel waveforms having a better coverage than Orthogonal Frequency Division Multiplexing (OFDM), beamforming and massive Multiple-input Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and multiantenna transmission technologies such as large-scale antennas. In addition, there has been ongoing discussion on new technologies for improving the coverage of terahertz-band signals, such as metamaterial-based lenses and antennas, Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS).

[0005] Moreover, in order to improve the spectral efficiency and the overall network performances, the following technologies have been developed for 6G communication systems: a full-duplex technology for enabling an uplink transmission and a downlink transmission to simultaneously use the same frequency resource at the same time; a network technology for utilizing satellites, High-Altitude Platform Stations (HAPS), and the like in an integrated manner; an improved network structure for supporting mobile base stations and the like and enabling network operation optimization and automation and the like; a dynamic spectrum sharing technology via collision avoidance based on a prediction of spectrum usage; an use of Artificial Intelligence (AI) in wireless communication for improvement of overall network operation by utilizing AI from a designing phase for developing 6G and internalizing end-to-end AI support functions; and a next-generation distributed computing technology for overcoming the limit of UE computing ability through reachable super-high-performance communication and computing resources (such as Mobile Edge Computing (MEC), clouds, and the like) over the network. In addition, through designing new protocols to be used in 6G communication systems, developing mechanisms for implementing a hardware-based security environment and safe use of data, and developing technologies for maintaining privacy, attempts to strengthen the connectivity between devices, optimize the network, promote softwarization of network entities, and increase the openness of wireless communications are continuing.

[0006] It is expected that research and development of 6G communication systems in hyper-connectivity, including person to machine (P2M) as well as machine to machine (M2M), will allow the next hyper-connected experience. Particularly, it is expected that services such as truly immersive eXtended Reality (XR), high-fidelity mobile hologram, and digital replica could be provided through 6G communication systems. In addition, services such as remote surgery for security and reliability enhancement, industrial automation, and emergency response will be provided through the 6G communication system such that the technologies could be applied in various fields such as industry, medical care, automobiles, and home appliances.

[0007] In order to meet an increasing demand for wireless data communication services since a deployment of 4G communication system, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called "beyond 4G network" or "post LTE system".

[0008] Wireless communication is one of the most successful innovations in modern history. Recently, a number of subscribers of wireless communication services has exceeded 5 billion, and it continues growing rapidly. With the increasing popularity of smart phones and other mobile data devices (such as tablet computers, notebook computers, netbooks, e-book readers and machine-type devices) in consumers and enterprises, a demand for wireless data services is growing rapidly. In order to meet rapid growth of mobile data services and support new applications and deployments, it is very important to improve efficiency and coverage of wireless interfaces.

[0009] According to an aspect of the disclosure, there is provided a method performed by a third node in a communication system, the method comprising: receiving a first message from a second node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, and transmitting a second message to the second node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node, wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.

[0010] According to the method performed by the third node in the communication system provided by the disclosure, wherein the first message further includes at least one of: fourth information for requesting configuration of the target cell for the handover of the first node; fifth information for requesting configuration of a candidate cell for the handover of the first node.

[0011] According to the method performed by the third node in the communication system provided by the disclosure, the first resource request information includes at least one of: resource request indication information, identification information of the base station, identification information of a distributed unit, identification information of a cell, information on the number of users served, carrier indication information, a preamble signal index, synchronization signal index information, a physical random access channel mask index; the fourth information includes at least one of: identification information of the target cell, first resource configuration information, which is used for generating configuration information related to measuring the candidate cell in the target cell by the third node; the fifth information includes at least one of: information related to layer 1 / layer 2 triggered mobility (LTM) handover; first configuration identification information, which is used to identify configuration corresponding to the candidate cell; identification information of a first candidate cell, which is used for identifying the candidate cell for the handover of the first node; second resource configuration information, which is used for generating configuration information related to measuring other candidate cells in the candidate cell for the handover of the first node by the third node, second resource request information for requesting resources of the third node.

[0012] According to the method performed by the third node in the communication system provided by the disclosure, wherein the third information includes at least one of: identification information of a second candidate cell, which is used to identify a candidate cell accepted or not accepted by the third node; second configuration identification information, which is used to identify configuration corresponding to the candidate cell accepted or not accepted by the third node; first user identification information, which is information related to an identification used when the first node accesses the base station where the cell is located; sixth information, including configuration of the candidate cell accepted or not accepted by the third node; first configuration request information, which is used to request the second node to provide configuration information of the candidate cell identified by the identification information of the second candidate cell or the second configuration identification information.

[0013] According to the method performed by the third node in the communication system provided by the disclosure, wherein the second message further includes at least one of: seventh information related to configuration of the target cell for the handover of the first node; eighth information related to configuration of a candidate cell for the handover of the first node.

[0014] According to the method performed by the third node in the communication system provided by the disclosure, wherein the method further comprises: receiving a third message from the second node, wherein the third message includes ninth information related to a candidate cell accepted by the third node and / or tenth information related to a base station serving the candidate cell accepted by the third node.

[0015] According to the method performed by the third node in the communication system provided by the disclosure, wherein the method further comprises: transmitting or receiving a fourth message to or from a fifth node serving the candidate cell, wherein the fourth message includes at least one of: second user identification information, including information related to identifying the first node on the third node and / or the fifth node; first release information, including information related to the one or more candidate cells allocated to the first node which needs to be released; first updated information, including information related to updated one or more candidate cells allocated to the first node.

[0016] According to the method performed by the third node in the communication system provided by the disclosure, wherein the method further comprises: transmitting a fifth message to a fourth node, wherein the fifth message includes second update information including information related to updated one or more candidate cells allocated to the first node, wherein the fourth node is a distributed unit (DU) and the third node is a centralized unit (CU).

[0017] According to the method performed by the third node in the communication system provided by the disclosure, wherein the first information, the sixth information, the eighth information or the ninth information, the first update information or the second update information further includes at least one of: third configuration identification information, which is used to identify configuration corresponding to the candidate cell; identification information of a third candidate cell, which is used for identifying a candidate cell configured to the first node; configuration information for a synchronization signal, including information related to configuration of the synchronization signal of the candidate cell; radio resource control (RRC) configuration information; thirteenth information, including information related to whether the RRC configuration information is a complete configuration; configuration information for synchronization, which is configuration information used to trigger the first node to acquire synchronization information of the candidate cell; configuration information for a beam, including information related to a beam used by the first node when transmitting a signal; resource configuration information of a reference signal, including information related to a resource of a reference signal of the candidate cell; first reset related configuration information, including information associated to determining reset related operations required by the third node when a cell of the first node changes; configuration information related to a first timing advance (TA) measurement, sharing indication information, wherein the indication information is shared by multiple user equipments, identification information of user equipment, identification information of a cell; a preamble signal index; carrier indication information, a synchronization signal index, a physical random access channel mask index, and information on usage time.

[0018] According to the method performed by the third node in the communication system provided by the disclosure, wherein the configuration information for synchronization includes at least one of: configuration information related to a random access channel required for early synchronization; configuration information related to a RACH-less random access channel; configuration information related to early uplink synchronization; configuration information related to contention free random access; configuration information related to a random access channel.

[0019] According to the method performed by the third node in the communication system provided by the disclosure, wherein the first reset related configuration information includes at least one of: fourteenth information, including information related to a reset operation associated with a cell identified by the identification information of the third candidate cell; first cell identification information, including information related to a cell without performing Layer 2 reset when the first node changes the cell; second cell identification information, including information related to a cell with performing Layer 2 reset when the first node changes the cell; wherein the configuration information related to a first timing advance (TA) measurement includes at least one of: fifteenth information, including information related to a measurement behavior of the first node associated with a cell identified by the identification information of the third candidate cell; third cell identification information, including information related to a cell to which the first node does not need to perform a measure based on a time advance of user terminal when the first node changes the cell; fourth cell identification information, including information related to a cell to which the first node needs to perform a measure based on a time advance of user terminal when the first node changes the cell.

[0020] According to the method performed by the third node in the communication system provided by the disclosure, wherein the second information or the tenth information includes at least one of: sixteenth information for indicating whether the second node has configured a candidate cell for the first node or for requesting the third node to accept the candidate cell configured to the first node.

[0021] According to another aspect of the disclosure, there is provided a method performed by a second node in a communication system, the method comprising: transmitting a first message to a third node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, and receiving a second message from the third node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node, wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.

[0022] According to the method performed by the second node in the communication system provided by the disclosure, wherein the first message further includes at least one of: fourth information for requesting configuration of the target cell for the handover of the first node; fifth information for requesting configuration of a candidate cell for the handover of the first node.

[0023] According to the method performed by the second node in the communication system provided by the disclosure, wherein the fourth information includes at least one of: identification information of the target cell; first resource configuration information, which is used for generating configuration information related to measuring the candidate cell in the target cell by the third node.

[0024] According to the method performed by the second node in the communication system provided by the disclosure, wherein the fifth information includes at least one of: information related to layer 1 / layer 2 triggered mobility (LTM) handover; first configuration identification information, which is used to identify configuration corresponding to the candidate cell; identification information of a first candidate cell, which is used for identifying the candidate cell for the handover of the first node; second resource configuration information, which is used for generating configuration information related to measuring other candidate cells in the candidate cell for the handover of the first node by the third node.

[0025] According to the method performed by the second node in the communication system provided by the disclosure, wherein the third information includes at least one of: identification information of a second candidate cell, which is used to identify a candidate cell accepted or not accepted by the third node; second configuration identification information, which is used to identify configuration corresponding to the candidate cell accepted or not accepted by the third node; first user identification information, which is information related to an identification used when the first node accesses the base station where the cell is located; sixth information, including configuration of the candidate cell accepted or not accepted by the third node; first configuration request information, which is used to request the second node to provide configuration information of the candidate cell identified by the identification information of the second candidate cell or the second configuration identification information.

[0026] According to the method performed by the second node in the communication system provided by the disclosure, wherein the second message further includes at least one of: seventh information related to configuration of the target cell for the handover of the first node; eighth information related to configuration of a candidate cell for the handover of the first node.

[0027] According to the method performed by the second node in the communication system provided by the disclosure, the method further comprises transmitting a third message to a third node, wherein the third message includes ninth information related to a candidate cell accepted by the third node and / or tenth information related to a base station serving the candidate cell accepted by the third node.

[0028] According to the method performed by the second node in the communication system provided by the disclosure, wherein the first information, the sixth information, the eighth information or the ninth information further includes at least one of: third configuration identification information, which is used to identify configuration corresponding to the candidate cell; identification information of a third candidate cell, which is used for identifying a candidate cell configured to the first node; configuration information for a synchronization signal, including information related to configuration of the synchronization signal of the candidate cell; radio resource control (RRC) configuration information; thirteenth information, including information related to whether the RRC configuration information is a complete configuration; configuration information for synchronization, which is configuration information used to trigger the first node to acquire synchronization information of the candidate cell; configuration information for a beam, including information related to a beam used by the first node when transmitting a signal; resource configuration information of a reference signal, including information related to a resource of a reference signal of the candidate cell; first reset related configuration information, including information associated to determining reset related operations required by the third node when a cell of the first node changes; configuration information related to a first timing advance (TA) measurement.

[0029] According to the method performed by the second node in the communication system provided by the disclosure, wherein the configuration information for synchronization includes at least one of: configuration information related to a random access channel required for early synchronization; configuration information related to a RACH-less random access channel; configuration information related to early uplink synchronization; configuration information related to contention free random access; configuration information related to a random access channel.

[0030] According to the method performed by the second node in the communication system provided by the disclosure, wherein the first reset related configuration information includes at least one of: fourteenth information, including information related to a reset operation associated with a cell identified by the identification information of the third candidate cell; first cell identification information, including information related to a cell without performing Layer 2 reset when the first node changes the cell; second cell identification information, including information related to a cell with performing Layer 2 reset when the first node changes the cell; wherein the configuration information related to a first timing advance (TA) measurement includes at least one of: fifteenth information, including information related to a measurement behavior of the first node associated with a cell identified by the identification information of the third candidate cell; third cell identification information, including information related to a cell to which the first node does not need to perform a measure based on a time advance of user terminal when the first node changes the cell; fourth cell identification information, including information related to a cell to which the first node needs to perform a measure based on a time advance of user terminal when the first node changes the cell.

[0031] According to the method performed by the second node in the communication system provided by the disclosure, wherein the second information or the tenth information includes at least one of: sixteenth information for indicating whether the second node has configured a candidate cell for the first node or for requesting the third node to accept the candidate cell configured to the first node.

[0032] According to the method performed by the second node in the communication system provided by the disclosure, wherein the method further comprises: transmitting a sixth message to a fifth node, wherein the sixth message includes at least one of: third resource configuration information, which is used for generating configuration information related to measuring other candidate cells in the candidate cell by the fifth node; second release information, which is information related to the one or more candidate cells allocated to the first node which needs to be released; eleventh information, which is configuration information related to a base station serving the first node; twelfth information, which is information related to the one or more candidate cells allocated to the first node.

[0033] According to the method performed by the second node in the communication system provided by the disclosure, wherein the eleventh information includes at least one of: identification information of a base station; identification information of a cell; third user identification information, which is information related to an identification used when the first node accesses the base station.

[0034] According to the method performed by the second node in the communication system provided by the disclosure, wherein the method further comprises: when the second node includes a centralized unit and a distributed unit, the centralized unit of the second node receives a third request message for requesting resources for transmitting a random access preamble signal transmitted by the distributed unit of the second node and the centralized unit of the second node transmits a third response message for resource allocation to the distributed unit of the second node; the third request message includes at least one of the following: identification information of a cell, carrier indication information and synchronization signal index information; and the third response message includes at least one of the following: a preamble signal index and a physical random access channel mask index.

[0035] According to the method performed by the second node in the communication system provided by the disclosure, wherein the method further comprises: transmitting a fifth message to a fourth node, wherein the fifth message includes second update information including information related to updated one or more candidate cells allocated to the first node, wherein the fourth node is a distributed unit (DU) and the third node is a centralized unit (CU).

[0036] According to another aspect of the disclosure, there is provided a method performed by a fifth node in a communication system, the method comprising: receiving a sixth message from a second node; and / or receiving a fourth message from a third node, wherein the sixth message or the fourth message includes information related to a candidate cell being updated.

[0037] According to the method performed by the fifth node in the communication system provided by the disclosure, wherein the sixth message includes at least one of: third resource configuration information, which is used for generating configuration information related to measuring other candidate cells in the candidate cell by the fifth node; second release information, which is information related to the one or more candidate cells allocated to the first node which needs to be released; eleventh information, which is configuration information related to a base station serving the first node; twelfth information, which is information related to the one or more candidate cells allocated to the first node.

[0038] According to the method performed by the fifth node in the communication system provided by the disclosure, wherein the fourth message includes at least one of: second user identification information, including information related to identifying the first node on the third node and / or the fifth node; first release information, including information related to the one or more candidate cells allocated to the first node which needs to be released; first updated information, including information related to updated one or more candidate cells allocated to the first node.

[0039] According to another aspect of the disclosure, there is provided a method performed by a fourth node in a communication system, the method comprising: receiving a fifth message from a second node; and / or receiving a fifth message from the third node, wherein the fifth message includes second update information including information related to updated one or more candidate cells allocated to a first node.

[0040] According to the method performed by the fourth node in the communication system provided by the disclosure, wherein the second update information further includes at least one of: third configuration identification information, which is used to identify configuration corresponding to the candidate cell; identification information of a third candidate cell, which is used for identifying a candidate cell configured to the first node; configuration information for a synchronization signal, including information related to configuration of the synchronization signal of the candidate cell; radio resource control (RRC) configuration information; thirteenth information, including information related to whether the RRC configuration information is a complete configuration; configuration information for synchronization, which is configuration information used to trigger the first node to acquire synchronization information of the candidate cell; configuration information for a beam, including information related to a beam used by the first node when transmitting a signal; resource configuration information of a reference signal, including information related to a resource of a reference signal of the candidate cell; first reset related configuration information, including information associated to determining reset related operations required by the third node when a cell of the first node changes; configuration information related to a first timing advance (TA) measurement.

[0041] According to another aspect of the disclosure, there is provided a third node comprising: a transceiver configured to transmit and receive signals with the outside; and a controller configured to control the transceiver to perform the above method performed by the third node.

[0042] According to another aspect of the disclosure, there is provided a second node comprising: a transceiver configured to transmit and receive signals with the outside; and a controller configured to control the transceiver to perform the above method performed by the second node.

[0043] According to another aspect of the disclosure, there is provided a fifth node comprising: a transceiver configured to transmit and receive signals with the outside; and a controller configured to control the transceiver to perform the above method performed by the fifth node.

[0044] According to another aspect of the disclosure, there is provided a fourth node comprising: a transceiver configured to transmit and receive signals with the outside; and a controller configured to control the transceiver to perform the above method performed by the fourth node.

[0045] According to another aspect of the disclosure, there is provided a non-transitory computer-readable recording medium having stored thereon a program which, when being executed by a computer, performs any of the above methods.

[0046] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide efficient communication methods in a wireless communication system.

[0047] Fig. 1 is an exemplary system architecture of System Architecture Evolution (SAE).

[0048] Fig. 2 is an exemplary system architecture according to various embodiments of the disclosure.

[0049] Fig. 3 is a schematic diagram of an interaction between a second node and a third node according to an embodiment of the disclosure.

[0050] Fig. 4 is a schematic diagram of an interaction between a second node and a fifth node according to an embodiment of the disclosure.

[0051] Fig. 5 is a schematic diagram of an interaction between a third node and a fifth node according to an embodiment of the disclosure.

[0052] Fig. 6 is a schematic diagram of a second node or a third node interacting with a fourth node according to an embodiment of the disclosure.

[0053] Fig. 7 is a block diagram illustrating the structure of a third node according to an embodiment of the disclosure.

[0054] Fig. 8 is a block diagram illustrating the structure of a second node according to an embodiment of the disclosure.

[0055] Fig. 9 is a block diagram illustrating the structure of a fifth node according to an embodiment of the disclosure.

[0056] Fig. 10 is a block diagram illustrating the structure of a fourth node according to an embodiment of the disclosure.

[0057] Fig. 11 is a block diagram illustrating the structure of a user equipment according to an embodiment of the disclosure.

[0058] Fig. 12 is a block diagram illustrating the structure of a base station according to an embodiment of the disclosure.

[0059] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide a terminal and a communication method thereof in a wireless communication system.

[0060] The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of various embodiments of the disclosure defined by the claims and their equivalents. This description includes various specific details to facilitate understanding but should only be considered as exemplary. Therefore, those skilled 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 disclosure. In addition, for the sake of clarity and conciseness, descriptions of well-known functions and structures may be omitted. In the disclosure, elements expressed in the singular form may also be understood to be expressed in the plural form. Similar words such as singular forms "a", "an" or "the" do not express a limitation of quantity, but express the existence of at least one of the referenced item, unless the context clearly dictates otherwise. For example, reference to "a component surface" includes reference to one or more of such surfaces.

[0061] The terms and expressions used in the following specification and claims are not limited to their dictionary meanings, but are only used by the inventors to enable a clear and consistent understanding of the disclosure. Therefore, it should be obvious to those skilled in the art that the following descriptions of various embodiments of the disclosure are provided for illustration purposes only and are not intended to limit the purposes of the disclosure as defined in the appended claims and their equivalents.

[0062] It should be understood that singular forms of "a", "an" and "the" include plural referents unless the context clearly indicates otherwise. Thus, for example, a reference to a "component surface" includes a reference to one or more such surfaces.

[0063] The terms "include" or "may include" refer to the existence of a corresponding disclosed function, operation or component that can be used in various embodiments of the disclosure, and do not limit the existence of one or more additional functions, operations or features. In addition, the terms "including" or "having" can 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 existence of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

[0064] The term "or" used in various embodiments of the 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.

[0065] Unless defined differently, all terms (including technical terms or scientific terms) used in this disclosure have the same meaning as those understood by those skilled in the art in this disclosure. Common terms, as defined in dictionaries, are interpreted as having meanings consistent with the context in the relevant technical fields, and should not be interpreted in an idealized or overly formal way unless explicitly defined in this disclosure.

[0066] Figs. 1 to 12 discussed below and various embodiments for describing the principles of the disclosure in this patent document are only for illustration and should not be interpreted as limiting the scope of the disclosure in any way. Those skilled in the art will understand that the principles of the disclosure can be implemented in any suitably arranged system or device.

[0067] Fig. 1 is an exemplary system architecture 100 of system architecture evolution (SAE). User equipment (UE) 101 is a terminal device for receiving data. An evolved universal terrestrial radio access network (E-UTRAN) 102 is a radio access network, which includes a macro base station (eNodeB / NodeB) that provides UE with interfaces to access the radio network. A mobility management entity (MME) 103 is responsible for managing mobility context, session context and security information of the UE. A serving gateway (SGW) 104 mainly provides functions of user plane, and the MME 103 and the SGW 104 may be in the same physical entity. A packet data network gateway (PGW) 105 is responsible for functions of charging, lawful interception, etc., and may be in the same physical entity as the SGW 104. A policy and charging rules function entity (PCRF) 106 provides quality of service (QoS) policies and charging criteria. A general packet radio service support node (SGSN) 108 is a network node device that provides routing for data transmission in a universal mobile telecommunications system (UMTS). A home subscriber server (HSS)109 is a home subsystem of the UE, and is responsible for protecting user information including a current location of the user equipment, an address of a serving node, user security information, and packet data context of the user equipment, etc.

[0068] Fig. 2 is an exemplary system architecture 200 according to various embodiments of the disclosure. Other embodiments of the system architecture 200 can be used without departing from the scope of the disclosure.

[0069] User equipment (UE) 201 is a terminal device for receiving data. A next generation radio access network (NG-RAN) 202 is a radio access network, which includes a base station (a gNB or an eNB connected to 5G core network 5GC, and the eNB connected to the 5GC is also called ng-gNB) that provides UE with interfaces to access the radio network. An access control and mobility management function entity (AMF) 203 is responsible for managing mobility context and security information of the UE. A user plane function entity (UPF) 204 mainly provides functions of user plane. A session management function entity SMF 205 is responsible for session management. A data network (DN) 206 includes, for example, services of operators, access of Internet and service of third parties.

[0070] The text and drawings are provided as examples only to help understand the disclosure. They should not be construed as limiting the scope of the disclosure in any way. Although certain embodiments and examples have been provided, based on the disclosure herein, it is obvious to those skilled in the art that changes can be made to the illustrated embodiments and examples without departing from the scope of this disclosure.

[0071] Before introducing the specific content, some assumptions and some definitions of the present invention are given below.

[0072] ■ The message names in the present invention are only examples, and other message names can be used.

[0073] ■ The "first" and "second" included in the message name of the present invention are only examples of messages and do not represent the execution order.

[0074] ■ Detailed description of steps irrelevant to the present invention is omitted in the present invention.

[0075] ■ In the present invention, the steps in each flow can be executed in combination with each other or independently. The execution steps of each process are only examples, and other possible execution orders are not excluded.

[0076] ■ In the present invention, the base station may be a 6G base station, a 5G base station (such as gNB and ng-eNB), a 4G base station (such as eNB) or other types of access nodes.

[0077] ■ In the present invention, when the cell accessed by the user equipment changes from one cell to another, this behavior can be called handover or cell switch. In the following description, handover and cell switch have the same meaning.

[0078] ■ In the invention, the user, the user equipment, the user terminal and the user terminal equipment are equivalent.

[0079] ■ In the present invention, the synchronization information may include at least one of the following information, for example:

[0080] ■ downlink synchronization information;

[0081] ■ uplink synchronization information such as timing advance information.

[0082] The nodes involved in the invention are:

[0083] ■ The first node: user terminal equipment, for example, which can be a mobile phone or a relay node.

[0084] ■ The second node: the base station, or the centralized unit of the base station, or the control plane part of the centralized unit of the base station, such as the source base station, or the centralized unit of the source base station, or the control plane part of the centralized unit of the source base station.

[0085] ■ The third node: the base station, or the centralized unit of the base station, or the control plane part of the centralized unit of the base station, for example, the target base station, or the centralized unit of the target base station, or the control plane part of the centralized unit of the target base station.

[0086] ■ The fourth node: for example, it can be a distributed unit of the target base station. The distributed unit can be the distributed unit where the target cell is located, or can be the distributed unit where candidate cell for the handover is located, or can be the distributed unit where the source cell is located. The target cell is a special cell (SpCell). In one example, the special cell can be a SpCell of a master cell group or a primary cell (PCell). In another example, the special cell can be a special cell of a secondary cell group or a primary secondary cell group cell (PSCell).

[0087] ■ The fifth node: the base station, or the centralized unit of the base station, or the control plane part of the centralized unit of the base station. For example, this node is a node serving the candidate cell allocated to the user terminal equipment.

[0088] In one example, the second node and the third node may be the same node.

[0089] The base station involved in the second / third / fifth node can be one of the following types (other types that can be used for user terminal access are not excluded), for example:

[0090] ■ LTE base station;

[0091] ■ 5G base station;

[0092] ■ 6G base station;

[0093] ■ NTN base station;

[0094] ■ HAPS base station;

[0095] ■ Drone base station;

[0096] ■ WIFI access point.

[0097] ■ The numbers of the following steps do not represent the order of the steps, and the following steps can be performed separately or in combination with each other.

[0098] In the invention, during the movement of the user terminal (the first node), the base station will configure two different types of cells for the first node:

[0099] ■ a target cell: which is the target cell for Layer 3 handover.

[0100] ■ a candidate cell: which is a cell for handover (or cell switch) prepared for the user terminal. In one example, this cell is a candidate cell for L1 / L2 triggered mobility (LTM) cell switch.

[0101] In the mobile network, user equipment will handover between different cells. During the handover, the communication of the user equipment will be interrupted. The main reason for the interruption is that the user equipment needs to measure for a long time. Before the handover, the network side needs to conduct signaling interaction between different nodes to determine the target cell and the configuration of the target cell, and then send a handover command to the user equipment. After that, the user equipment needs to perform uplink and downlink synchronization with the network. In this process, it takes a long time for the user to change cells, which further affects the user's performance in the mobile process. Therefore, it is necessary to enhance the handover process of user equipment.

[0102] In some embodiments, when the user equipment is moving, the network side will configure the user equipment for cell handover. One handover method is handover based on Layer 3 signaling, that is, the base station sends Layer 3 signaling (Layer 3 handover command) to the user equipment, and after the user equipment receives this signaling, it interrupts the communication with the source cell and starts the process of accessing the target cell. In this process, the user equipment will occur communication interruption. In order to reduce the time delay or communication interruption of user terminals during handover, a cell handover method based on Layer 1 / Layer 2 signaling, namely LTM, is proposed. Specifically, in the process of LTM cell switch, the network side will trigger the user terminal to hand over through layer 1 or layer 2 signaling. Furthermore, before triggering the user terminal to hand over, the user terminal can also acquire the time advance information required to access the target cell in advance, such as through the measurement of the user terminal, or transmitting a random access signal in advance.

[0103] How to configure cell switch triggered by Layer 1(L1) / Layer 2(L2) signaling when configuring Layer 3 (L3) handover is an urgent problem to be solved. In addition, when configuring the candidate cell of LTM, it is also necessary to allocate resources for user equipment to access the candidate cell, such as random access resources. How to improve the efficiency of resource allocation is also an urgent problem to be solved.

[0104] An embodiment of the disclosure provides a method performed by a third node in a communication system, the method comprising: receiving a first message from a second node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, and transmitting a second message to the second node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node, wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.

[0105] An embodiment of the disclosure provides a method performed by a second node in a communication system, the method comprising: transmitting a first message to a third node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, and receiving a second message from the third node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node, wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.

[0106] In this way, it is possible to configure both Layer 3 handover and LTM (L1 / L2 triggered mobility) handover at the same time. For example, when the user equipment performs handover based on Layer 3 signaling, the network side can configure the candidate cell of LTM for the user equipment. In this way, after the user equipment accesses the target cell, the cell switch based on LTM can be performed in the target cell, thus reducing the communication interruption of the user equipment in the handover process.

[0107] Hereinafter, the methods of configuring layer 3 handover and / or LTM handover provided by various embodiments of the disclosure will be described in detail with reference to Figs. 3 to 7.

[0108] Fig. 3 is a schematic diagram of an interaction between a second node and a third node according to an embodiment of the disclosure. In one example, the flow shown in Figure 3 is used to configure L3 handover; in another example, the flow shown in Fig. 3 is used to configure the candidate cell (such as the LTM candidate cell); in another example, the flow shown in Fig. 3 is used to configure both L3 handover and the candidate cell (such as the LTM candidate cell). The beneficial effects of this process are that the user is configured with handover to reduce communication interruption, and the interruption of data transmission caused by user movement is reduced. As shown in Figure 3, the process may include one or more of the following steps 1-1 to 1-3:

[0109] Step 1-1: The second node sends a first request message (for example, it can also be called the first message or other message names, and the name of the message is not limited in the present invention) to the third node. In one embodiment,the message is used to configure the cell of the first node (the user terminal). In one example, the cell can be the target cell for the handover of the first node (such as the target cell of Layer 3 handover). The target cell is the cell served by the third node. In another example, the cell may be a candidate cell (such as a candidate cell of LTM). The candidate cell is a cell served by the third node. After receiving the message, the third node will generate the related configuration of the target cell or candidate cell, and then configure the first node (for example, the second node configures the first node), the message can be a user equipment associated message, such as a Handover Request message. In another embodiment, the message is information for resource allocation interacting between the second node and the third node, such as interacting resource allocation information related to random access, and the message can be a non-user equipment associated message, such as a configuration update request message, an interface establishment request message, a resource allocation request message, etc. The message includes at least one of the following information:

[0110] ■ Target cell configuration request information (for example, it can also be called the fourth information or other information names, and the name of the message is not limited in the present invention), which is used to request the configuration of the target cell. In one example, the target cell is the target cell of Layer 3 handover. After receiving this information, the third node will determine whether the target cell can be used as the target for handover of the first node, and if so, the third node will also prepare resources for serving the first node and generate configuration information for serving the first node. The information includes at least one of the following information:

[0111] ■ Identification information of the target cell, such as PCI (Physical Cell Identifier), NR CGI (New Radio Cell Global Identifier), etc.

[0112] ■ First resource configuration information, which is used to help the third node generate configuration information related to measuring the candidate cell in the target cell. In one example, the information is configuration information of CSI (Channel State Information) resources, which can help the third node to generate configuration information related to CSI measurement (such as measurement configuration information and measurement report configuration information). Further, the information may be resource configuration information related to all candidate cells (such as LTM candidate cells) configured to the first node. Specifically, the information includes identification information of the configuration of the candidate cell (configuration identification, or candidate identification), resource information of SSB (SS / PBCH block) of the candidate cell, and index information of SSB (SSB Index). After receiving this information, the third node will generate configuration information for measuring these candidate cells according to the candidate cells allocated to the first node (or according to the candidate cells acceptable to the third node).

[0113] ■ First resource request information, which is used to request the third node to allocate resources. One example of this resource is a Random Access resource, another example is a RACH-less resource, and another example is a Early (UL) synchronization resource. This requested resource can be used by the first node to trigger the user to send a random access signal, so as to obtain random access information (such as time advance information). Further, the information can be used to request new resources, or to request the addition of new resources, or to request the release of resources. The beneficial effect of this information is that the third node can allocate resources according to the requirement of the second node, thus improving the efficiency of resource utilization. The information includes at least one of the following information:

[0114] ■ Resource request indication information, which is used to indicate that a new resource is requested, or that an allocated resource is requested to be released, or that a new resource is requested to be added. The request indication information can be explictinformation or implicit indication, such as determined by the name of the information (for example, resource to be added and resource to be released);

[0115] ■ Identification information of the base station, such as identification information of gNB.

[0116] ■ Identification information of a distributed unit, such as identification information of the distributed unit of the base station and identification information of gNB-DU (gNB distributed unit).

[0117] ■ Identification information of a cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the UE.

[0118] ■ Information on the number of users served, which indicates the number of users served by the resources requested in the "first resource request information", and the number of users can be an estimated information or an accurate information, and the third node will determine the number of allocated resources according to this information. In one example, the resources requested by the above-mentioned "first resource request information" are shared by multiple users, and in the subsequent process, the second node will allocate resources to one user according to the request of the user or other nodes;

[0119] ■ Carrier indication information indicating a carrier where the requested resource is located, such as a normal uplink carrier and a supplementary uplink carrier.

[0120] ■ Signal index information indicating the index of the allocated physical signal, such as the Preamble Index.

[0121] ■ Synchronization signal index information, which indicates the index of the synchronization signal. In one example, the synchronization signal is SSB(SS / PBCH (Physical Broadcast Channel) block), then the index information is SSB Index.

[0122] ■ Index information of the resource, which indicates the index information of the requested resource. In one example, the index information is physical random access channel mask index (PRACH Mask Index) information;

[0123] ■ Candidate cell configuration request information (for example, it can also be called the fifth information or other information name, and the name of the message is not limited in the present invention), which is used to request the configuration of candidate cells (such as LTM candidate cells). After receiving this information, the third node will determine whether the candidate cell can be used as the candidate for the handover of the first node, and if so, the third node will also prepare resources for serving the first node and generate configuration information for serving the first node. The information includes at least one of the following information:

[0124] ■ Information related to the L1 / L2 triggered mobility (LTM), for example, it may be handover indication information, which indicates that the candidate cell is used to configure LTM for users, such as LTM indicator.

[0125] ■ Configuration identification information (for example, it can also be called the first configuration identification information or other information name, and the name of the message is not limited in the present invention), which identifies the configuration corresponding to the candidate cell, such as LTM configuration identification and LTM candidate identification.

[0126] ■ Identification information of the candidate cell (for example, it can also be called the identification information of the first candidate cell or other information name, and the name of the message is not limited in the present invention), which is used to identify the candidate cell configured to the first node, such as PCI, NR CGI, etc.

[0127] ■ Second resource configuration information, which is used to help the third node generate configuration information related to measuring other candidate cells in the candidate cell. In one example, the information is configuration information of CSI (Channel State Information) resources, which can help the third node to generate configuration information related to CSI measurement (such as measurement configuration information and measurement report configuration information). Further, the information may be resource configuration information related to all candidate cells (such as LTM candidate cells) configured to the first node. Specifically, the information includes identification information of the configuration of the candidate cell (configuration identification, or candidate identification), resource information of SSB (SS / PBCH block) of the candidate cell, and index information of SSB (SSB Index). After receiving this information, the third node will generate configuration information for measuring these candidate cells according to the candidate cells allocated to the first node (or according to the candidate cells acceptable to the third node).

[0128] ■ Second resource request information, which is used to request the resources of the third node. For the description of this information, please refer to the above-mentioned "First Resource Request Information".

[0129] ■ First assistant information of the cell (for example, it can also be called the second information or other information names, and the name of the message is not limited in the present invention), which indicates the assistant information used to help the third node determine the cell configuration. In one example, the cell may be a candidate cell configured to the first node, in another example, it may be a target cell configured for the first node, and in another example, it may be a serving cell of the first node. The information has the beneficial effects of helping the third node to know the base station of the cell serving the first node, facilitating the third node to update the configuration of the cell with the base station, and reducing the communication interruption of the first node in the subsequent moving process when the first node accesses the third node. The information includes at least one of the following information:

[0130] ■ Cell configuration indication information (for example, it can also be called sixteenth information or other information names, and the name of the information is not limited by the present invention), and one possible function of this information is to indicate whether a candidate cell is configured for the first node, and another possible function is to request the third node to accept the candidate cell configured to the first node. After receiving this information, the third node can decide whether to accept the candidate cell allocated to the first node.

[0131] ■ Information related to the base station, the function of which is to indicate the configuration information related to the base station of the candidate cell or the target cell or the serving cell. After receiving this information, the third node can carry out signaling interaction with the base station according to this information, so as to carry out subsequent configuration (for example, after the user accesses the target cell or candidate cell served by the third node, the third node updates the configuration of the candidate cell with the base station of the candidate cell, see the signaling interaction flow in steps 2-1 and 2-2 below). The information includes at least one of the following information:

[0132] ◆ Identification information of the base station (such as the fifth node) where the cell is located;

[0133] ◆ Identification information of the cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the UE.

[0134] ◆ Identification information of the user equipment, in one example, it indicates the identification information used when the first node accesses the base station where the cell is located, such as the identification information of the air interface (C-RNTI) , the identification information of the interface of the base station (such as XnAP UE ID, further, the ID is the identification information of the first node on the fifth node side). When the third node carries out signaling interaction with the base station where the cell is located, the third node can include the identification in the signaling. In one example, the identification can be named as a context ID, or it can be named by other names.

[0135] ■ First configuration information of the candidate cell (for example, it can also be called the first information or other information names, and the name of the message is not limited in the present invention), which is used to provide configuration information related to one or more candidate cells configured to the first node (in one example, the candidate cell is a candidate cell of LTM). In one example, when configuring one candidate cell for the first node (such as when the first request message contains the above-mentioned "candidate cell configuration request information"), the information is used to provide the third node with other candidate cells configured for the first node; in another example, when configuring a target cell for the first node (e.g., the first request message contains the above-mentioned "target cell configuration request information"), the information provides information of candidate cells configured to the first node. After receiving this information, the third node can know the candidate cell allocated to the first node, so as to determine the LTM cell switch after the first node accesses the target cell or the candidate cell. The information may contain configuration information of one or more candidate cells, that is, the information may be a list. In one example, the information may be contained in the first request message in the form of a container containing configuration information related to all candidate cells configured to the first node, such as LTM configuration (LTM-config). In another example, this information may be contained in Handover preparation information container, and the container contains configuration information related to all candidate cells allocated to the first node, such as LTM configuration (LTM-config). In another example, this information may be contained in the first request message in the form of explicit information element. The information has the beneficial effects of helping the third node to obtain the information of the candidate cell configured to the first node, so that the third node can configure the first node for cell handover and reduce the interruption of communication. For one candidate cell, the information includes at least one of the following information (in one example, the configuration information for one candidate cell may be included in the LTM Candidate information element):

[0136] ■ Configuration identification information (for example, it can also be called the third configuration identification information or other information name, and the name of the message is not limited in the present invention), which identifies the configuration corresponding to the candidate cell, such as LTM configuration identification and LTM candidate identification.

[0137] ■ Identification information of the candidate cell (for example, it can also be called the identification information of the third candidate cell or other information names, and the name of the message is not limited in the present invention), which indicates the candidate cell configured to the first node, such as PCI, NR CGI, etc.

[0138] ■ Configuration information of the synchronization signal, which indicates the configuration information of the synchronization signal of the candidate cell. In one example, this information is configuration information of SSB, such as LTM SSB configuration, which can be used for the first node to perform L1 measurement for the candidate cell. Specifically, the information includes at least one of the following information: frequency point information (such as SSB Frequency), subcarrier spacing information (such as a subcarrier spacing), period information (SSB periodicity), position information (such as SSB position in burst), and power information (such as SSB power).

[0139] ■ RRC configuration information, such as candidate configuration, such as configuration information contained in RRC Reconfiguration message.

[0140] ■ Indication information of complete configuration (for example, it can also be called thirteenth information or other information names, and the invention does not impose any restrictions on the names of information), which is information related to whether the RRC configuration information is a complete configuration. This information indicates whether the above-mentioned "RRC configuration information" is a complete configuration, for example, a configuration complete indicator.

[0141] ■ Configuration information of synchronization, which, in one example, is used by the third node to trigger the user terminal to acquire synchronization information (such as time advance information) of the candidate cell. The information includes at least one of the following information:

[0142] ◆ Configuration of Random Access Channel (RACH) required for early synchronization, or the configuration of RACH-less, or the configuration of early uplink synchronization. This configuration information is used for the first node to acquire the synchronization information of the candidate cell (or send a random access signal to the candidate cell) before receiving a handover command (such as a command for triggering the user to perform the LTM cell switch, LTM MAC Control Element). In one example, the information is configuration information on a normal uplink carrier, in another example, it is configuration information on a supplementary uplink carrier, and in another example, it includes both configuration information on a normal uplink carrier and configuration information on a supplementary uplink carrier. For normal uplink carrier or supplementary uplink carrier, the information includes at least one of the following information:

[0143] ● Frequency domain indication information, which indicates the frequency domain information of a random access signal (such as a random access preamble) sent by the first node, such as the frequency point of the normal uplink carrier, the frequency point of the supplementary uplink carrier, and configuration information of bandwidth part (BWP) (such as BWP ID);

[0144] ● Sequence related information, which indicates the sequence used for the transmitted random access signal, such as prach-RootSequenceIndex;

[0145] ● A time alignment timer, which indicates the valid time of the time advance, such as a time advance timer;

[0146] ● RACH generic configuration, which indicates generic configuration information for transmitting the random access signal, including at least one of the following information: random access channel configuration index information (prach-configurationIndex), a target power that the network receiver side receives preamble (preambleReceivedTargetPower), a maximum number that the preamble is transmitted (premableTransMax), an increase step size of transmission power of preamble (powerRampingSetp), a size of random access response window ra-(ResponseWindow), etc.

[0147] ● RACH dedicated configuration, which indicates dedicated configuration information for transmitting the random access signal. The information may be different for different users, and includes at least one of the following information: RACH occasion information (which indicates resources for transmitting the random access signal), a number of SSBs corresponding to each RACH occasion (ssb-perRACH-occasion), configuration information of resources (such as a mask index used for random access resource selection (physical random access channel mask index)), ab index of the corresponding SSB or CSI-RS (SSB / CSIRS-index), and an index of the preamble (ra-PreambleIndex);

[0148] ◆ Configuration information related to contention free random access, or RACH-based configuration information, which is used for the first node to acquire synchronization information of the candidate cell (or send a random access signal to the candidate cell) when receiving a handover command (such as a command for triggering the user to perform the LTM cell switch). In one example, when a first node receives a handover command (such as a command of LTM cell switch), the first node will send a random access signal according to the information in the handover command, and then acquire synchronization information (such as timing advance) of the candidate cell. In one example, the information is configuration information on a normal uplink carrier, in another example, it is configuration information on a supplementary uplink carrier, and in another example, it includes both configuration information on a normal uplink carrier and configuration information on a supplementary uplink carrier. For the normal uplink carrier or the supplementary uplink carrier, the information includes at least one of the following information:

[0149] ● Frequency domain indication information;

[0150] ● Sequence related information;

[0151] ● A time alignment timer;

[0152] ● RACH generic configuration;

[0153] ● RACH dedicated configuration.

[0154] For the detailed description of the above information, please refer to the description of each information in the above "Configuration of Random Access Channel (RACH) required for early synchronization ".

[0155] ■ Configuration information of a beam, which indicates the beam used by the first node when transmitting the signal (such as the random access signal). The information includes at least one of the following information:

[0156] ◆ Indication information of a downlink beam, such as a transmission configuration indication (TCI) state index (TCI state index).

[0157] ◆ Indication information of an uplink beam, such as a TCI status index.

[0158] ◆ Indication information of an uplink and downlink beam, in one example, this information is joint TCI state indication information, such as a TCI state index.

[0159] ■ Resource configuration information of a reference signal, which indicates the resources of the reference signal of the candidate cell, and contains at least one of the following information:

[0160] ◆ Configuration information of resources of CSI-RS (Channel State Information-Reference Signal);

[0161] ◆ Configuration information of resources of NZP (non-zero-power) -CSI-RS;

[0162] ◆ Configuration information of resources of the reference signal for path loss estimation, and the reference signal indicated by this information is used for path loss estimation.

[0163] ■ 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. The information includes at least one of the following information:

[0164] ◆ The first indication information (for example, it can also be called fourteenth information or other information names, and the name of the information is not limited by the present invention) that identifies No Reset, which is information related to the reset operation associated with the cell identified by the identification information of the third candidate cell, such as no reset ID. The information can indicate the information of the reset operation associated with the cell indicated by the above-mentioned "identification information of the candidate cell". In one example, this information is used to determine whether a Layer 2 reset is required when the first node is triggered by to perform the procedure of LTM cell switch (such as the third node triggers the procedure or the first node triggers the procedure on the selected cell). After receiving this information, the third node will determine whether the reset operation is needed (such as, whether to perform L2 reset), according to the cell switch of the first node (for example, changing from the cell indicated by the above-mentioned "identification information of the candidate cell" to the other cell, or changing from the other cell 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 LTM, and in another example, the other cell is not a candidate cell of LTM) and the indication information. The information has the beneficial effects of helping the third node to know whether the first node has performed the L2 reset, realizing the same behavior as the first node, and reducing the delay of the cell switch of the first node when the Layer 2 reset is not performed.

[0165] ◆ Identification information of first cell without reset (for example, it can also be called the first cell identification information or other information names, and the name of the information is not limited by the present invention), which is information related to the cell that does not need to perform Layer 2 reset when the first node switches the cell. The cell indicated by this information can be the cell that the does not need to perform Layer 2 reset when the first node switches the cell, and in one embodiment, this cell is a candidate cell of LTM. In one example, if the cell of the first node is changed from the cell indicated by the "identification information of first cell without reset" to the cell indicated by the above-mentioned "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 is changed from the cell indicated by the "identification information of the candidate cell" to the cell indicated by the "identification information of first cell without reset", the third node does not need to perform Layer 2 reset.

[0166] ◆ Identification information of first cell that needs to be reset (for example, it can also be called the second cell identification information or other information names, and the name of the information is not limited in the present invention), which is information related to the cell that needs to perform Layer 2 reset when the first node switches the cell, and the cell indicated by this information can be the cell that needs to perform Layer 2 reset when the first node switches the cell, and in one embodiment, the cell is a candidate cell of LTM. In one example, if the cell of the first node is changed from the cell indicated by the "identification information of first cell that needs to be reset" to the cell indicated by the "identification information of the candidate cell", the third node needs to perform layer 2 reset; in another example, if the cell of the first node is changed from the cell indicated by the "identification information of the candidate cell" to the cell indicated by the "identification information of first cell that needs to be reset", the third node needs to perform Layer 2 reset.

[0167] ■ configuration information related to a first timing advance (TA) measurement. In one example, the configuration information is used to instruct to perform the measurement of the time advance, such as UE-based TA measurement. The function of this information is to help the third node determine whether the first node performs the measurement of the time advance when the first node switches the cell. The information includes at least one of the following information:

[0168] ◆ First indication information identifying the TA measurement (for example, it can also be called fifteenth information or other information names, and the name of the information is not limited by the present invention), including information related to a measurement behavior of the first node associated with a cell identified by the identification information of the third candidate cell, such asUE-Measured TA ID. The information can indicate the measurement behaviour (performing UE-based TA measurement) of the first node associated with the cell indicated by the above-mentioned "identification information of the candidate cell". In one example, this information is used to determine whether it is necessary to perform UE-based TA measurement when or before the first node performs the process of LTM cell switch (for example, the third node triggers the procedure or the first node triggers the procedure on the selected cell). After receiving this information, the third node will determine whether the first node performs UE-based TA measurement, according to the cell switch of the first node (for example, changing from the cell indicated by the above-mentioned "identification information of the candidate cell" to the other cell, or changing from the other cell 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 LTM, and in another example, the other cell is not a candidate cell of LTM) and the indication information. Further, the third node will determine whether to trigger the first node to acquire the time advance in advance. The information has the beneficial effects of helping the third node to know whether the first node has performed UE-based TA measurement, thereby optimizing the resource allocation and avoiding the trigger of unnecessary time advance acquisition (or early uplink synchronization).

[0169] ◆ Identification information of first cell without TA measurement (for example, it can also be called the third cell identification information or other information names, and the name of the information is not limited in the present invention), which is information related to the cell that does not need to perform UE-based TA measurement when the first node switches the cell, and the cell indicated by this information can be the cell that does not perform UE-based TA measurement when the first node switches the cell. In one example, if the cell of the first node is changed from the cell indicated by the "identification information of first cell without TA measurement" to the cell indicated by the "identification information of the candidate cell", the first node does not perform UE-based TA measurement; in another example, if the cell of the first node is changed from the cell indicated by the "identification information of the candidate cell" to the cell indicated by "identification information of first cell without TA measurement", the first node does not perform UE-based TA measurement.

[0170] ◆ Identification information of first cell that needs to measure (for example, it can also be called fifteenth information, or other information names, and the name of the information is not limited in the present invention), which is information related to the cell that needs to perform UE-based TA measurement when the first node switches the cell, and the cell indicated by this information can be the cell that needs to perform UE-based TA measurement when the first node switches the cell. In one example, if the cell of the first node is changed from the cell indicated by the "identification information of first cell that needs to measure" to the cell indicated by the above "identification information of the candidate cell", the first node needs to perform UE-based TA measurement; in another example, if the cell of the first node is changed from the cell indicated by the "identification information of the candidate cell" to the cell indicated by the "identification information of first cell that needs to measure", the first node needs to perform UE-based TA measurement.

[0171] Step 1-2: The third node sends a first response message to the second node (for example, it can also be called the second message or other message names, and the name of the message is not limited in the present invention). In one embodiment, the message is used to provide configuration information of the target cell or candidate cell, and the configuration information can be used to configure the first node for L3 handover or LTM. This message can be a user equipment associated message, such as a Handover Request Acknowledge message. In another embodiment, the message is information for resource allocation interacting between the second node and the third node, such as interacting resource allocation information related to random access, and the message can be a non-user equipment associated message, such as a configuration update response message, an interface establishment response message, a resource allocation response message, etc. The message includes, for example, at least one of the following information:

[0172] ■ Target cell configuration response information (for example, it can also be called the seventh information or other information names, and the name of the information is not limited in the present invention), which includes the configuration information related to the target cell generated by the third node, and in one example, this information includes the information contained in the RRC Reconfiguration message. When the third node agrees to use the target cell as the target cell of the first node, the first response message will contain this information.

[0173] ■ Candidate cell configuration response information (for example, it can also be called the eighth information or other information name, and the name of the information is not limited by the present invention), which contains the configuration information related to the candidate cell generated by the third node (such as the response to the above "candidate cell configuration request information", that is, the third node agrees to configure the candidate cell indicated in the above "candidate cell configuration request information" as the candidate cell of the first node). In one example, the information is a container that contains the configuration information of candidate cells, such as LTM candidate. In another example, the information contains various configuration information related to candidate cells, which are included in the first response message in an explicit manner (such as explicit Information element). In one embodiment, the information is a response to the above-mentioned "first resource request information". The information has the advantages of providing the configuration information of candidate cells, facilitating the configuration of resources for handover for user equipment in advance, and reducing the interruption and delay of handover. The information includes at least one of the following information (please refer to the above-mentioned "First configuration information of the candidate cell" for the description of each information contained in the information):

[0174] ■ Configuration identification information;

[0175] ■ Identification information of a base station, such as identification information of gNB.

[0176] ■ Identification information of a distributed unit, such as identification information of a distributed unit of a base station and identification information of gNB-DU(gNB distributed unit).

[0177] ■ Identification information of the candidate cell;

[0178] ■ Configuration information of the synchronization signal;

[0179] ■ RRC configuration information;

[0180] ■ Indication information of complete configuration;

[0181] ■ Configuration information of synchronization;

[0182] ■ Configuration information of a beam;

[0183] ■ Resource configuration information of a reference signal;

[0184] ■ First reset related configuration information;

[0185] ■ configuration information related to a first timing advance (TA) measurement.

[0186] ■ Sharing indication information, which indicates that at least one information contained in the "candidate cell configuration response information" is shared by multiple user equipments. Based on this information, the second node can allocate the resources indicated in the "candidate cell configuration response information" (such as the resources indicated in the "Configuration information of synchronization") to multiple users. The information has the advantages of reducing signaling interaction between nodes, reducing resource waste by sharing resources, and improving the efficiency of resource use;

[0187] ■ Identification information of user equipment

[0188] ■ Identification information of a cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the user equipment.

[0189] ■ Signal index information indicating the index of the allocated physical signal, such as the Preamble Index.

[0190] ■ Carrier indication information indicating the carrier where the requested resource is located, such as a normal uplink carrier and a supplementary uplink carrier.

[0191] ■ Second synchronization signal Index information, which indicates the index of the synchronization signal. In one example, the synchronization signal is SSB(SS / PBCH(Physical Broadcast Channel) block), and the index information is SSB Index.

[0192] ■ Index information of the resource, which indicates the index information of the requested resource. In one example, the index information is physical random access channel mask index information;

[0193] ■ Information on usage time, which indicates the time during which the resource requested by the second node is used, that is, during the time indicated by the information, the second node can use the resource, otherwise, it will not use the resource;

[0194] ■ Request rejection indication information, which indicates that the third node rejects the request of the second node, or that the third node has no resources to allocate. This information can be explicit indication information or implicit indication information. In addition, the information can also include the configuration information of the rejected resources, which can refer to the information indicated by the above-mentioned "First configuration information of the candidate cell" or "Candidate cell configuration response information", and according to this information, the second node can know which requested resources are rejected or cannot be allocated.

[0195] ■ Response information related to the configured candidate cell (for example, it can also be called the third information or other information names, and the name of the information is not limited by the present invention), which indicates the information of the candidate cell that has been configured to the first node and accepted by the third node, or indicates the information of the candidate cell that has been configured to the first node and cannot be accepted by the third node. In one example, the accepted or not accepted candidate cell is a candidate cell configured by the second node to the first node, such as a candidate cell configured to the first node in the source cell. The response message may be a response to "auxiliary information of the candidate cell" in the first request message or a response to "first configuration information of the candidate cell" in the first request message. The information has the beneficial effects of helping the second node to know the candidate cell accepted by the third node, thereby releasing or updating the candidate cell allocated to the first node and improving the resource utilization efficiency of the base station serving the candidate cell. The information may include information of one or more candidate cells, and for one candidate cell, the information includes, for example, one of the following information:

[0196] ■ Identification information of the candidate cell (for example, it can also be called the identification information of the second candidate cell or other information names, and the name of the message is not limited in the present invention), such as PCI, NR CGI, etc.

[0197] ■ Configuration identification information (for example, it can also be called the second configuration identification information or other information name, and the name of the information is not limited in the present invention), which identifies the configuration corresponding to the candidate cell, such as LTM configuration identification and LTM candidate identification.

[0198] ■ Second user identification information (for example, it can also be called the first user identification information or other information name, and the name of the information is not limited in the present invention), in one example, the information indicates the identification information used when the first node accesses the base station where the cell is located, such as the identification information of the air interface (C-RNTI) , the identification information of the interface of the base station (such as XnAP UE ID), and further, the ID is the identification information of the first node on the third node side). When the third node interacts with the base station where the candidate cell is located, the third node can include the identification information in the signaling to update the configuration of the candidate cell.

[0199] ■ Second configuration information of the candidate cell (for example, it can also be called the sixth information or other information names, and the name of the information is not limited by the present invention), which contains the configuration of one or more candidate cells accepted by the third node, and the information contained in this information can be referred to the description in the above-mentioned "First configuration information of the candidate cell".

[0200] ■ First configuration request information, which is used to request the second node to provide configuration information of the cell identified by "identification information of the candidate cell" or the "configuration identification information". After receiving this information, the second node will provide the information of the candidate cell to the third node in the following steps. In one example, the cell identified by the "identification information of the candidate cell" is a cell accepted by the third node.

[0201] Step 1-3: Optionally, the second node sends a first acknowledge message to the third node (for example, it can also be called the third message or other message names, and the name of the message is not limited in the present invention), and the function of this message is to provide the third node with the information of the candidate cell configured to the first node. When the information of the candidate cell configured to the first node is not provided in the first request message, this step can be used to provide the configuration information of the candidate cell. In one example, the first acknowledgement message is a response to the "response information related to the configured candidate cell" in the first response message. An example of this message is SN (sequence number) status transfer. The message includes at least one of the following information:

[0202] ■ The second assistant information of the cell (for example, it can also be called the tenth information, or other information names, and the name of the message is not limited in the present invention), which is used to indicate the configuration information related to the base station serving the cell of the first node. In one example, the cell may be a candidate cell configured to the first node, in another example, it may be a target cell configured to the first node, and in another example, it may be a serving cell of the first node. After receiving this information, the third node will carry out signaling interaction with the base station of the cell serving the first node according to this information so as to carry out subsequent configuration (for example, after the user accesses the target cell served by the third node, the third node will update the configuration of the candidate cell with the base station of the candidate cell, as shown in the signaling interaction flow in steps 2-1 and 2-2 below). The information includes at least one of the following information:

[0203] ■ Cell configuration indication information, one possible function of which is to indicate whether a candidate cell is configured to the first node, and another possible function is to request the third node to accept the candidate cell configured to the first node. After receiving this information, the third node can decide whether to accept the candidate cell allocated to the first node.

[0204] ■ Information related to the base station, the function of which is to indicate the configuration information related to the base station of the candidate cell or the target cell or the serving cell. After receiving this information, the third node can carry out signaling interaction with the base station according to this information, so as to carry out subsequent configuration (for example, after the user accesses the target cell or candidate cell served by the third node, the third node updates the configuration of the candidate cell with the base station of the candidate cell, see the signaling interaction flow in steps 2-1 and 2-2 below). The information includes at least one of the following information:

[0205] ◆ Identification information of the base station (such as the fifth node) where the cell is located.

[0206] ◆ Identification information of the cell, such as PCI, NR CGI, etc.

[0207] ◆ The identification information of the third user, in one example, indicates the identification information used when the first node accesses the base station where the cell is located, such as the identification information of the air interface (C-RNTI) , the identification information of the interface of the base station (such as XnAP UE ID, further, the ID is the identification information of the first node on the fifth node side). When the third node performs signaling interaction with the base station where the cell is located, the third node can include the identification in the signaling. In one example, the identification can be named as a context ID, or it can be named by other names.

[0208] ■ The third configuration information of the candidate cell (for example, it can also be called the ninth information, or other information name, and the name of the message is not limited in the present invention), which contains the configuration information of one or more candidate cells configured to the first node. For the specific information contained in this information, please refer to "First configuration information of the candidate cell" in the above step 1-1.

[0209] Step 1-4: The second node sends a first user configuration message to the first node, which is used to configure the target cell or candidate cell for handover of the first node, and the message includes at least one of the following information:

[0210] ■ Configuration information of the target cell, which includes configuration information related to the target cell, such as random access configuration information, bearer configuration information, and cell group configuration information (CellGroupConfig).

[0211] ■ Fifth configuration information of the candidate cell, and the specific information contained in this information can be found in "First Configuration Information of the Candidate Cell" in Step 1-1 above.

[0212] The above process has the advantages of helping the third node to obtain the information of the candidate cell allocated to the first node, so as to determine the accepted candidate cell, configuring the LTM cell switch after the first node accesses the third node, and reducing the communication interruption of the first node in the moving process.

[0213] The first request message in the above process may be a Handover Request message, configuration update request message, a Resource request message, or other messages.

[0214] The first response message in the above process may be a Handover Request Acknowledge message, configuration update response message, a resource response message, or other messages.

[0215] The first acknowledge message in the above flow may be an SN status transfer message or other messages.

[0216] Through the above method, it is possible to configure both Layer 3 handover and LTM (L1 / L2 triggered mobility) handover at the same time, that is, when the user equipment performs handover based on Layer 3 signaling, the network side can configure candidate cells of LTM for the user equipment. In this way, after the user equipment accesses the target cell, the cell switch based on LTM can be performed in the target cell, thus reducing the communication interruption of the user equipment in the handover process.

[0217] Through the above method, the resource request can be realized, and the requested resource can be served by one or more users served by the first node. In a specific embodiment, the above method can realize the request of resources for random access, which is used to obtain the uplink time advance information of the cell served by the third node. After receiving the requested resources, the first node can allocate them to different users. When the first node contains a centralized unit and a distributed unit, the requested resources can also be used by users served by different distributed units in the first node. Specifically, the distributed unit of the first node can send a request message to the centralized unit of the first node, which is used to request the centralized unit of the first node to allocate random access resources, and then the distributed unit of the first node will allocate the requested random access resources to the user equipment. For a detailed description of this process, please refer to the description in the subsequent part of the present invention.

[0218] For example, the above process can have the following possible implementations:

[0219] When the first request message is used to prepare a target cell for L3 handover, possible implementations are as follows:

[0220] Embodiment 1: The information of the configured candidate cell is sent by a first request message.

[0221] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0222] ■ Target cell configuration request information;

[0223] ■ First assistant information of the cell;

[0224] ■ First configuration information of the candidate cell.

[0225] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0226] ■ Target cell configuration response information;

[0227] ■ Response information related to the configured candidate cell.

[0228] Embodiment 2: The information of the configured candidate cell is sent through the first acknowledge message, and the third node obtains the candidate cell configured to the first node through the "first configuration information of the candidate cell" contained in the first request message.

[0229] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0230] ■ Target cell configuration request information;

[0231] ■ First configuration information of the candidate cell.

[0232] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0233] ■ Target cell configuration response information;

[0234] ■ Response information related to the configured candidate cell.

[0235] Step 1-3: The second node sends a first acknowledge message to the third node, which contains at least one of the following information:

[0236] ■ Second assistant information of the cell;

[0237] ■ Third configuration information of the candidate cell.

[0238] Embodiment 3: The assistant information of the cell is sent through the first acknowledge message, and the third node obtains the information of the configured candidate cell through the "first configuration information of the candidate cell" contained in the first request message.Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0239] ■ Target cell configuration request information;

[0240] ■ First assistant information of the cell, which does not contain information related to the base station of the candidate cell;

[0241] ■ First configuration information of the candidate cell.

[0242] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0243] ■ Target cell configuration response information;

[0244] ■ Response information related to the configured candidate cell.

[0245] Step 1-3: The second node sends a first acknowledge message to the third node, which contains at least one of the following information:

[0246] ■ Second assistant information of the cell.

[0247] When the first request message is used to prepare a candidate cell for the LTM, possible implementations are as follows:

[0248] Embodiment 4: The information of the configured candidate cell is sent through the first request message.

[0249] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0250] ■ Candidate cell configuration request information;

[0251] ■ First assistant information of the cell;

[0252] ■ First configuration information of the candidate cell.

[0253] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0254] ■ Candidate cell configuration response information;

[0255] ■ Response information related to the configured candidate cell.

[0256] Embodiment 5: The information of the configured candidate cell is sent through the first acknowledge message, and the third node obtains the candidate cell configured to the first node through the "first configuration information of the candidate cell" contained in the first request message.

[0257] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0258] ■ Candidate cell configuration request information;

[0259] ■ First configuration information of the candidate cell.

[0260] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0261] ■ Candidate cell configuration response information;

[0262] ■ Response information related to the configured candidate cell.

[0263] Step 1-3: The second node sends a first acknowledge message to the third node, which contains at least one of the following information:

[0264] ■ Second assistant information of the cell;

[0265] ■ Third configuration information of the candidate cell.

[0266] Embodiment 6: The assistant information of the cell is sent through the first acknowledge message, and the third node obtains the information of the configured candidate cell through the "first configuration information of the candidate cell" contained in the first request message.

[0267] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0268] ■ Candidate cell configuration request information;

[0269] ■ First assistant information of the cell, which does not contain information related to the base station of the candidate cell;

[0270] ■ First configuration information of the candidate cell.

[0271] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0272] ■ Candidate cell configuration response information;

[0273] ■ Response information related to the configured candidate cell.

[0274] Step 1-3: The second node sends a first acknowledge message to the third node, which contains at least one of the following information:

[0275] ■ Second assistant information of the cell.

[0276] When the first request message is used to prepare a target cell for L3 handover and a candidate cell of LTM, possible implementations are as follows:

[0277] Embodiment 7: The information of the configured candidate cell is sent through the first request message.

[0278] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0279] ■ Target cell configuration request information;

[0280] ■ Candidate cell configuration request information;

[0281] ■ First assistant information of the cell;

[0282] ■ First configuration information of the candidate cell.

[0283] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0284] ■ Target cell configuration response information;

[0285] ■ Candidate cell configuration response information;

[0286] ■ Response information related to the configured candidate cell.

[0287] Embodiment 8: The information of the configured candidate cell is sent through the first acknowledge message, and the third node obtains the candidate cell configured to the first node through the "first configuration information of the candidate cell" contained in the first request message.

[0288] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0289] ■ Target cell configuration request information;

[0290] ■ Candidate cell configuration request information;

[0291] ■ First configuration information of the candidate cell.

[0292] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0293] ■ Target cell configuration response information;

[0294] ■ Candidate cell configuration response information;

[0295] ■ Response information related to the configured candidate cell.

[0296] Step 1-3: The second node sends a first acknowledge message to the third node, which contains at least one of the following information:

[0297] ■ Second assistant information of the cell;

[0298] ■ Third configuration information of the candidate cell.

[0299] Embodiment 9: The assistant information of the cell is sent through the first acknowledge message, and the third node obtains the information of the configured candidate cell through the "first configuration information of the candidate cell" contained in the first request message.

[0300] Step 1-1: The second node sends a first request message to the third node, which includes at least one of the following information:

[0301] ■ Target cell configuration request information;

[0302] ■ Candidate cell configuration request information;

[0303] ■ First assistant information of the cell, which does not contain information related to the base station of the candidate cell;

[0304] ■ First configuration information of the candidate cell.

[0305] Step 1-2: The third node sends a first response message to the second node, which includes at least one of the following information:

[0306] ■ Target cell configuration response information;

[0307] ■ Candidate cell configuration response information;

[0308] ■ Response information related to the configured candidate cell.

[0309] Step 1-3: The second node sends a first acknowledge message to the third node, which contains at least one of the following information:

[0310] ■ Second assistant information of the cell.

[0311] When the first request message is a request for resources, possible implementations are as follows:

[0312] Embodiment 10:

[0313] Step 1-1: The second node sends a first request message to the third node, which includes the above-mentioned "first resource request information";

[0314] Step 1-2: The third node sends a first response message to the second node, which includes the "candidate cell configuration response information";

[0315] Further, when the third node includes a centralized unit and a distributed unit, after the above step 1-1, it further includes:

[0316] Step 1-1a: The centralized unit of the third node sends a second request message to the distributed unit of the third node, which is used to configure the cell of the first node or to request resource allocation from the distributed unit of the third node. For the information contained in this message, please refer to the above-mentioned "First Request Message";

[0317] Step 1-1b: The distributed unit of the third node sends a second response message to the centralized unit of the third node, which is used to provide the configuration information of the cell allocated to the first node or the configuration information of the resources allocated by the third node. Further, the information may also include configuration update indication information, which indicates that the information contained in the second response message is an update to the existing configuration. Based on the configuration information obtained in this step, the third node (or the centralized unit of the third node) can provide the above-mentioned "first response message" to the second node.

[0318] When the second node includes a centralized unit and a distributed unit, the following steps may be included after the above step 1-2:

[0319] Step 1-2-1: The centralized unit of the second node sends a first modification request message to the distributed unit of the second node, which includes the configuration information of the candidate cell configured for the first node. The specific information contained in this message can be found in the "First Configuration Information of the Candidate Cell" in the above step 1-1 or the "Candidate Cell Configuration Response Information" in the above step 1-2. Further, the information may also include at least one of the following information:

[0320] ■ Release request indication information indicating released resources. One example of this resource is a Random Access resource, another example is a RACH-less resource, and another example is an Early (UL) synchronization resource. The information contains at least one of the following information:

[0321] ◆ Identification information of the cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the user equipment.

[0322] ◆ Configuration information of released resources, and the information contained in this information can be referred to the above-mentioned " configuration information for synchronization ".

[0323] ■ First resource request indication information indicating that the distributed unit of the second node needs to send a request message to the centralized unit of the second node to obtain resources. In one embodiment, after the distributed unit of the second node obtains the resource configuration information of the first node through the above-mentioned step 1-2-1 (in one example, the resource configured by the configuration information is Random Access resource, or RACH-less resource, or an Early (UL) synchronization resource, it cannot be directly used, and it needs to send to the centralized unit of the second node again, which will allocate the resource again. After receiving this information, the distributed unit of the second node will send a request message to the centralized unit of the second node when it wants to use resources.

[0324] When the distributed unit of the second node wants to trigger the random access procedure (or the Early (UL) synchronization process) of the first node, it also includes the following steps:

[0325] Step 1-2-2: The distributed unit of the second node sends a third request message to the centralized unit of the second node, which is used to request resources, and the requested resources are used for the first node to send physical signals. In one embodiment, this step occurs after the above step 1-2-1, which provides a set of resources (as indicated by the above-mentioned "First Configuration Information of the Candidate Cell" or "Candidate Cell Configuration Response Information"), and step 1-2-2 is used to request specific resources used by the first node. In another embodiment, when the distributed unit of the second node needs to trigger the first node to send a physical signal, it sends the third request message to request resources. In one example, the physical signal is a random access signal (such as a preamble signal of random access), which is used to help the first node obtain the time advance information to access the candidate cell. The message has the beneficial effects that the distributed unit of the second node can request resources according to the requirements of the first node, flexibly utilize the resources allocated by the third node (for example, the resources can be shared by multiple different user equipment), and improve the efficiency of resource utilization. The third request message includes at least one of the following information:

[0326] ■ Assistant information for requesting resources, which helps the centralized unit of the second node to allocate resources, and which can be used to request one or more resources. One example of this resource is a Random Access resource, another example is a RACH-less resource, and another example is an Early (UL) synchronization resource. The information has the beneficial effects of helping the centralized unit of the second node to select appropriate resources used by the first node and improving the efficiency of resource utilization. For a requested resource, at least one of the following information is included:

[0327] ■ Identification information of user equipment

[0328] ■ Identification information of the cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the user equipment.

[0329] ■ Carrier indication information indicating the carrier where the requested resource is located, such as a normal uplink carrier and a supplementary uplink carrier.

[0330] ■ Synchronization signal index information, which indicates the index of the synchronization signal. In one example, the synchronization signal is SSB(SS / PBCH(Physical Broadcast Channel) block), then the index information is SSB Index.

[0331] ■ Information on first usage time, which indicates the time during which the resource requested by the distributed unit of the second node is used, that is, during the time indicated by the information, the distributed unit of the second node can use the resource, otherwise, it will not use the resource;

[0332] ■ Information on requested resources, which indicates the resources requested by the distributed unit of the second node or the resources used by the distributed unit of the second node. After receiving this information, the centralized unit of the second node will decide whether the requested resources or the used resources can be used by the distributed unit of the second node. The beneficial effect of this information is that the distributed unit of the second node can select appropriate resources according to the state of the first node, help the centralized unit of the second node to allocate appropriate resources, and improve the efficiency of resource utilization. The information includes at least one of the following information:

[0333] ■ Identification information of user equipment

[0334] ■ Identification information of the cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the user equipment.

[0335] ■ Carrier indication information indicating the carrier where the requested resource is located, such as a normal uplink carrier and a supplementary uplink carrier.

[0336] ■ Signal index information indicating the index of the allocated physical signal, such as the Preamble Index.

[0337] ■ Synchronization signal index information, which indicates the index of the synchronization signal. In one example, the synchronization signal is SSB(SS / PBCH(Physical Broadcast Channel) block), then the index information is SSB Index.

[0338] ■ Index information of the resource, which indicates the index information of the requested resource. In one example, the index information is physical random access channel mask index (PRACH Mask Index) information;

[0339] ■ Information on the second usage time, which indicates the time during which the resource requested by the distributed unit of the second node is used, that is, during the time indicated by the information, the distributed unit of the second node can use the resource, otherwise, it will not use the resource;

[0340] Further, the above-mentioned "Assistant information for requesting resources " and "Information on requested resources" are methods for different resource requests. The former is to request resources from the centralized unit of the second node by providing auxiliary information, while the latter is that the distributed unit of the second node first determines the resources, and then sends the determined resources to the centralized unit of the second node, and the centralized unit of the second node determines whether the requested resources are available.

[0341] Step 1-2-3: The centralized unit of the second node sends a third response message to the distributed unit of the second node, which is used to allocate resources, so that the distributed unit of the second node can use the allocated resources to trigger the first node to send physical signals, such as random access signals (such as random access preamble signals). Further, the centralized unit of the second node may also have no resources to allocate, so the first modification response message can also be used to reject the resource request or indicate that the resource request failed. The message includes at least one of the following information:

[0342] ■ Identification information of user equipment

[0343] ■ Identification information of the cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the user equipment.

[0344] ■ First resource information, which indicates the allocated resources. The resource configuration information contained in this information can refer to the information indicated in the above-mentioned "First Configuration Information of the Candidate Cell" or "Candidate Cell Configuration Response Information". In addition, for a signal of random access, the information may also include one or more allocated resources, and for a resource, the information includes at least one of the following information:

[0345] ■ Signal index information indicating the index of the allocated physical signal, such as the Preamble Index.

[0346] ■ Carrier indication information indicating the carrier where the requested resource is located, such as a normal uplink carrier and a supplementary uplink carrier.

[0347] ■ Second synchronization signal index information, which indicates the index of the synchronization signal. In one example, the synchronization signal is SSB(SS / PBCH(Physical Broadcast Channel) block), so the index information is SSB Index.

[0348] ■ Index information of the resource, which indicates the index information of the requested resource. In one example, the index information is physical random access channel mask index (PRACH Mask Index) information;

[0349] ■ Information on third usage time, which indicates the time during which the resource requested by the distributed unit of the second node is used, that is, during the time indicated by the information, the distributed unit of the second node can use the resource, otherwise, it will not use the resource;

[0350] ■ Request rejection indication information, which indicates that the centralized unit of the second node rejects the request of the distributed unit of the second node, or indicates that the centralized unit of the second node has no resources to allocate. This information can be explicit indication information or implicit indication information. In addition, the information can also include the configuration information of the rejected resources, which can refer to the information indicated by the above-mentioned "First configuration information of the candidate cell" or "Candidate cell configuration response information", and according to this information, the distributed unit of the second node can know which requested resources are rejected or cannot be allocated.

[0351] Step 1-2-4: The distributed unit of the second node sends a trigger message to the first node, which is used to trigger the first node to send a physical signal, and one function of the physical signal is to help the first node obtain the time advance information to access the candidate cell. The message includes at least one of the following information:

[0352] ■ Identification information of the cell, such as PCI, NR CGI, etc. Optionally, the identification information of the cell includes the identification information of the candidate cell configured for the user equipment.

[0353] ■ Carrier indication information indicating the carrier where the requested resource is located, such as a normal uplink carrier and a supplementary uplink carrier.

[0354] ■ Synchronization signal index information, which indicates the index of the synchronization signal. In one example, the synchronization signal is SSB(SS / PBCH(Physical Broadcast Channel) block), then the index information is SSB Index.

[0355] ■ Index information of the resource, which indicates the index information of the requested resource. In one example, the index information is physical random access channel mask index (PRACH Mask Index) information;

[0356] In the above flow, the centralized unit of the second node can first obtain the set of resources from the third node, and then the distributed unit of the second node requests the required resources from the centralized unit of the second node when necessary. This way is conducive to sharing the requested set of resources by multiple users and improving the efficiency of resource utilization.

[0357] In the following, taking the physical signal sent by the first node as a random access signal (or a random access preamble signal) as an example, the implementation of resource request is introduced.

[0358] Embodiment 11: The centralized unit of the second node obtains the set of resources, and then allocates the resources according to the request of the distributed unit of the second node. In this embodiment, when the centralized unit of the second node allocates resources, it selects appropriate resources from a set of resources from the third node, thus reducing the signaling interaction with the third node for requesting resources and improving the efficiency of utilizing these resources at the second node.

[0359] Step a: The second node or the centralized unit of the second node sends a first request message to the third node, and the information contained in this message can be referred to the description in Step 1-1 above.

[0360] Step b: the third node sends a first response message to the second node or the centralized unit of the second node, which contains the configuration information of resources, and the information contained in this message can be referred to the description in the above step 1-2;

[0361] Step c: The distributed unit of the second node sends a third request message to the centralized unit of the second node, and the description of this message can refer to the above step 1-2-2. In one example, the distributed unit of the second node requests the centralized unit of the second node to allocate resources by providing the above-mentioned "Assistant information for requesting resources"; In another example, the distributed unit of the second node requests to allocate the resources indicated by the information through the above-mentioned "information on requested resources";

[0362] Step d: The centralized unit of the second node sends a third response message to the distributed unit of the second node, which is used to indicate the allocated resources or reject the requested resources, and the information contained in this message can be referred to the above step 1-2-3;

[0363] Optionally, before step c, it may further include:

[0364] Step c-0: The centralized unit of the second node sends a first modification request message to the distributed unit of the second node, which is used to allocate the set of resources obtained from the third node to the distributed unit of the second node. When the distributed unit of the second node obtains the allocated resources through the above step d, it can trigger the first node to send physical signals, such as random access signals, in combination with the information in the message.

[0365] Embodiment 12: The distributed unit of the second node requests resources through the centralized unit of the second node. In this embodiment, the distributed unit of the second node always requests resources through the centralized unit of the second node when it needs resources, thus avoiding unnecessary waste of resources (if the third node needs to reserve a set of resources according to theEmbodiment 11, this may lead to waste of resources) and improving the efficiency of resource utilization.

[0366] Step a: the distributed unit of the second node sends a third request message to the centralized unit of the second node, and the information contained in this message can refer to the above step 1-2-2;

[0367] Step b: the second node or the centralized unit of the second node sends a first request message to the third node, and the information contained in this message can be referred to the description in the above step 1-1.

[0368] Step c: the third node sends a first response message to the second node or the centralized unit of the second node, and the information contained in this message can be referred to the description in step 1-2 above.

[0369] Step d: The centralized unit of the second node sends a third response message to the distributed unit of the second node, which is used to indicate the allocated resources or reject the requested resources, and the information contained in this message can be referred to the above step 1-2-3;

[0370] Optionally, before step d, it may further include:

[0371] Step d-0: The centralized unit of the second node sends a first modification request message to the distributed unit of the second node, which is used to allocate resources obtained from the third node to the distributed unit of the second node, and then the distributed unit of the second node triggers the first node to send physical signals, such as random access signals.

[0372] Please continue to refer to Fig. 4, which is a schematic diagram of interaction between a second node and a third node according to an embodiment of the disclosure.

[0373] After step 1-2, the second node can know the candidate cells that are accepted by the third node and have been allocated to the first node, and the candidate cells that are not accepted by the third node and have been allocated to the first node. Therefore, further, as shown in Fig. 4, the above method may further include one or more of steps 1-2a to 1-2b:

[0374] Step 1-2a: The second node sends a first configuration update message (for example, it can also be called the sixth message or other message names, and the name of the message is not limited by the present invention) to the fifth node, which is a base station serving the candidate cell configured to the first node, and the message is used to inform the configuration information that candidate cell is updated. The message includes at least one of the following information:

[0375] ■ Third resource configuration information, which is used to help the fifth node generate configuration information related to measuring other candidate cells in the candidate cell. In one example, the information is configuration information of CSI (Channel State Information) resources, which can help the third node to generate configuration information related to CSI measurement (such as measurement configuration information and measurement report configuration information). Further, the information may be resource configuration information related to all candidate cells (such as LTM candidate cells) configured to the first node. Specifically, the information includes identification information of the configuration of the candidate cell (configuration identification, or candidate identification), resource information of SSB (SS / PBCH block) of the candidate cell, and index information of SSB (SSB Index). After receiving this information, the fifth node will generate configuration information for measuring these candidate cells according to the candidate cells configured to the first node.

[0376] ■ Information of the released candidate cell (for example, it can also be called the second release information or other information names, and the name of the information is not limited by the present invention), which indicates the candidate cell allocated to the first node which needs to be released, and includes at least one of the following information:

[0377] ■ Identification information of the candidate cell, such as PCI and NR CGI.

[0378] ■ Configuration identification information, which identifies the configuration corresponding to the candidate cell, such as LTM configuration identification and LTM candidate identification.

[0379] ■ The third assistant information of the cell (for example, it can also be called eleventh information or other information names, and the name of the message is not limited in the present invention), which is used to indicate the configuration information related to the base station serving the first node (such as the third node). The base station may be the base station where the candidate cell or the target cell or the serving cell of the first node is located. After receiving this information, the fifth node will carry out signaling interaction with the base station serving the first node according to this information, so as to carry out subsequent configuration of the candidate cell (for example, interaction with the third node, see the signaling interaction flow in steps 2-1 and 2-2 below). The information includes at least one of the following information:

[0380] ■ Identification information of the base station (such as the third node) where the cell is located. The base station where the cell is located may be the base station where the candidate cell of the first node is located, or the base station where the serving cell of the first node is located, or the base station where the target cell of the first node is located.

[0381] ■ Cell identification information, such as PCI, NR CGI, etc., in one example, this information can be used to indicate a candidate cell accepted by the third node, and in another example, the cell indicated by this information can be a serving cell or a target cell where the first node is located, or a candidate cell of the first node.

[0382] ■ The identification information of the fourth user (for example, it can also be called the third user identification information or other information names, and the name of the information is not limited by the present invention), in one example, this information indicates the identification information used when the first node accesses the base station, such as the identification information of the air interface (C-RNTI) and the identification information of the interface of the base station (such as XnAP UE ID), and further, the ID is the identification information of the first node on the third node side). When the third node interacts with the fifth node in signaling, the fifth node can include the identification information in the signaling, so as to update the configuration of the candidate cell.

[0383] ■ Fourth configuration information of the candidate cell (for example, it can also be called twelfth information or other information names, and the name of the information is not limited by the present invention), which contains the configuration information of the candidate cell configured to the first node. For the specific information contained in this information, please refer to "First Configuration Information of the Candidate Cell" in the above step 1-1.

[0384] Step 1-2b: The fifth node sends a first configuration update response message to the second node, which is used to update the configuration of the candidate cell served at the fifth node. The message may include the configuration information of the candidate cell, and the information contained in this information may refer to "First Configuration Information of the Candidate Cell" in Step 1-1 above.

[0385] Please continue to refer to Fig. 5, which is a schematic diagram of interaction between a third node and a fifth node according to an embodiment of the disclosure.

[0386] Through the above step 1-1 or step 1-3, the third node can know the serving base station (such as the fifth node) of the candidate cell allocated to the first node, and through the above step 1-2a, the fifth node can know the base station (such as the third node) accessed by the first node. After that, the third node and the fifth node can carry out the candidate configuration process of candidate cells, such as releasing candidate cells, adding new candidate cells and updating the configuration of existing candidate cells. Therefore, further, as shown in Fig. 5, the above method may further include one or more of steps 2-1 to 2-2:

[0387] Step 2-1: The third node sends a second configuration update message to the fifth node (or the fifth node sends it to the third node) (for example, it can also be called the fourth message or other message names, and the name of the message is not limited in the present invention), which includes at least one of the following information:

[0388] ■ User identification information (for example, it can also be called the second user identification information or other information name, and the name of the message is not limited in the present invention), which is used to identify the first node at the third node and / or the fifth node, such as the above-mentioned first user identification information or the third user identification information, and / or the above-mentioned second user identification information or the fourth user identification information.

[0389] ■ Information of the released candidate cell (for example, it can also be called the first release information or other information names, and the invention does not impose any restrictions on the names of information), such as cell identification, configuration identification, etc.

[0390] ■ Configuration information of the updated candidate cell (for example, it can also be called the first updated information or other information names, and the name of the information is not limited by the present invention), and the specific content of this information can be referred to "first configuration information of the candidate cell" in the above step 1-1.

[0391] Step 2-2: The fifth node sends a second configuration update response message to the third node (or the third node sends it to the fifth node), which includes at least one of the following information:

[0392] ■ User identification information, which is used to identify the first node at the third node and / or the fifth node, such as the first user identification information or the third user identification information, and / or the second user identification information or the fourth user identification information.

[0393] ■ Configuration information of the updated candidate cell. For details of this information, please refer to "First Configuration Information of the Candidate Cell" in Step 1-1 above.

[0394] The first configuration update message or the second configuration update message may be a Handover Request message or other messages.

[0395] The first configuration update response message or the second configuration update response message may be a Handover Request Acknowledge message or other messages.

[0396] The above process has the advantages that the configuration of the candidate cell of the first node on the network side is updated, so that the configured candidate cell is still maintained after the service cell of the first node is changed, thereby reducing the data interruption of subsequent handover.

[0397] Please continue to refer to Fig. 6, which is a schematic diagram of an interaction between a second node or a third node and a fourth node according to an embodiment of the disclosure.

[0398] When the second node or the third node obtains the configuration information of the candidate cell, it will also provide the fourth node with the configuration information of the updated candidate cell. Therefore, further, as shown in Fig. 6, the above method may further include one or more of steps 3-1 to 3-2:

[0399] Step 3-1: The second node or the third node sends a third configuration update message (for example, it can also be called the fifth message or other message names, and the name of the message is not limited by the present invention) to the fourth node, which can include the configuration information of the updated candidate cell, for example, it can be called the second update information or other message names (for details, please refer to "First Configuration Information of the Candidate Cell" in Step 1-1 above).

[0400] Step 3-2: The fourth node sends a third configuration update response message to the second node or the third node, which provides the configuration information of the updated candidate cell at the fourth node (please refer to "First Configuration Information of the Candidate Cell" in the above step 1-1 for details).

[0401] The third configuration update message may be a UE context setup / modification request message or other messages.

[0402] The third configuration update response message may be a UE context setup / modification response message or other messages.

[0403] The above process has the beneficial effects that the configuration information related to the candidate cell served at the distributed unit of the first node is updated, which is convenient for the distributed unit to trigger the first node to hand over, and the interruption of data transmission of the switch is reduced.

[0404] In addition, it can be understood that the contents contained in each message in the above-mentioned embodiment are only examples of this disclosure, and the contents contained in various similar or identical messages can be replaced with each other, or named with different names, or some items can be added or deleted according to the situation, and for the sake of brevity, the meanings of similar content items can be mutually explained according to the context without being repeated, and the modified and explained embodiments still belong to the scope of protection of the present invention.

[0405] Fig. 7 is a block diagram illustrating the structure of a third node 400 according to an embodiment of the disclosure.

[0406] Referring to Fig. 7, the third node 400 includes a transceiver 401 and a controller 402. The transceiver 401 is configured to transmit and receive signals to and from the outside. The controller 402 is configured to perform the above-described method performed by the third node. The third node 400 may be implemented in the form of hardware, software, or a combination of hardware and software, so that it can perform the method performed by the first node described in the disclosure.

[0407] Fig. 8 is a block diagram illustrating the structure of a second node 500 according to an embodiment of the disclosure.

[0408] Referring to Fig. 8, the second node 500 includes a transceiver 501 and a controller 502. The transceiver 501 is configured to transmit and receive signals to and from the outside. The controller 502 is configured to perform a method performed by the second node. The second node 500 may be implemented in the form of hardware, software, or a combination of hardware and software, so that it can perform the method performed by the second node described in the disclosure.

[0409] Fig. 9 is a block diagram illustrating the structure of a fifth node 600 according to an embodiment of the disclosure.

[0410] Referring to Fig. 9, the fifth node 600 includes a transceiver 601 and a controller 602. The transceiver 601 is configured to transmit and receive signals to and from the outside. The controller 602 is configured to perform a method performed by a fifth node. The fifth node 600 may be implemented in the form of hardware, software, or a combination of hardware and software, so that it can perform the method performed by the fifth node described in the disclosure.

[0411] Fig. 10 is a block diagram illustrating the structure of a fourth node 700 according to an embodiment of the disclosure.

[0412] Referring to Fig. 10, the fourth node 700 includes a transceiver 701 and a controller 702. The transceiver 701 is configured to transmit and receive signals to and from the outside. The controller 702 is configured to perform a method performed by a fourth node. The fourth node 700 may be implemented in the form of hardware, software, or a combination of hardware and software, so that it can perform the method performed by the fourth node described in the disclosure.

[0413] Fig. 11 is a block diagram illustrating the structure of a user equipment according to an embodiment of the disclosure.

[0414] As shown in FIG. 11, the UE according to an embodiment may include a transceiver 1110, a memory 1120, and a processor 1130. The transceiver 1110, the memory 1120, and the processor 1130 of the UE may operate according to a communication method of the UE described above. However, the components of the UE are not limited thereto. For example, the UE may include more or fewer components than those described above. In addition, the processor 1130, the transceiver 1110, and the memory 1120 may be implemented as a single chip. Also, the processor 1130 may include at least one processor. Furthermore, the UE of FIG. 11 corresponds to a UE according to embodiments of the disclosure.

[0415] The transceiver 1110 collectively refers to a UE receiver and a UE transmitter, and may transmit / receive a signal to / from a base station or a network entity. The signal transmitted or received to or from the base station or a network entity may include control information and data. The transceiver 1110 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 1110 and components of the transceiver 1110 are not limited to the RF transmitter and the RF receiver.

[0416] Also, the transceiver 1110 may receive and output, to the processor 1130, a signal through a wireless channel, and transmit a signal output from the processor 1130 through the wireless channel.

[0417] The memory 1120 may store a program and data required for operations of the UE. Also, the memory 1120 may store control information or data included in a signal obtained by the UE. The memory 1120 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0418] The processor 1130 may control a series of processes such that the UE operates as described above. For example, the transceiver 1110 may receive a data signal including a control signal transmitted by the base station or the network entity, and the processor 1130 may determine a result of receiving the control signal and the data signal transmitted by the base station or the network entity.

[0419] Fig. 12 is a block diagram illustrating the structure of a base station according to an embodiment of the disclosure.

[0420] As shown in FIG. 12, the base station according to an embodiment may include a transceiver 1210, a memory 1220, and a processor 1230. The transceiver 1210, the memory 1220, and the processor 1230 of the base station may operate according to a communication method of the base station described above. However, the components of the base station are not limited thereto. For example, the base station may include more or fewer components than those described above. In addition, the processor 1230, the transceiver 1210, and the memory 1220 may be implemented as a single chip. Also, the processor 1230 may include at least one processor. Furthermore, the base station of FIG. 12 corresponds to a base station according to embodiments of the disclosure.

[0421] The transceiver 1210 collectively refers to a base station receiver and a base station transmitter, and may transmit / receive a signal to / from a terminal (UE) or a network entity. The signal transmitted or received to or from the terminal or a network entity may include control information and data. The transceiver 1210 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 1210 and components of the transceiver 1210 are not limited to the RF transmitter and the RF receiver.

[0422] Also, the transceiver 1210 may receive and output, to the processor 1230, a signal through a wireless channel, and transmit a signal output from the processor 1230 through the wireless channel.

[0423] The memory 1220 may store a program and data required for operations of the base station. Also, the memory 1220 may store control information or data included in a signal obtained by the base station. The memory 1220 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0424] The processor 1230 may control a series of processes such that the base station operates as described above. For example, the transceiver 1210 may receive a data signal including a control signal transmitted by the terminal, and the processor 1230 may determine a result of receiving the control signal and the data signal transmitted by the terminal.

[0425] At least one embodiment of the disclosure also provides a non-transitory computer-readable recording medium, on which a program for executing the above method when a computer runs has been stored.

[0426] Various embodiments of the disclosure can be realized 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 disk read-only memory (CD-ROM), magnetic tape, floppy disk, optical data storage device, carrier wave (for example, data transmission via the Internet), and the like. Computer-readable recording media can be distributed through computer systems connected via a network, and thus computer-readable codes can be stored and executed in a distributed manner. Moreover, functional programs, codes and code segments for implementing various embodiments of the disclosure can be easily interpreted by those skilled in the art to which the embodiments of the disclosure are applied.

[0427] It will be understood that the embodiments of the disclosure can be implemented in the form of hardware, software, or a combination of hardware and software. The software can be stored as program instructions or computer-readable code 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.). Non-transient computer-readable recording media can also be distributed on network-coupled computer systems, so that computer-readable codes are stored and executed in a distributed manner. The medium can 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-transitory computer-readable recording medium suitable for storing program (s) having instructions for implementing embodiments of the disclosure. The disclosure can be realized by a program having codes for concretely implementing the apparatus and method described in the claims, which is 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 this disclosure suitably includes its equivalents.

[0428] What has been described above is only the specific implementation of this disclosure, but the protection scope of this disclosure is not limited to this. Any person familiar with this technical field can make various changes or substitutions within the technical scope disclosed in this disclosure, and these changes or substitutions should be included in the protection scope of this disclosure. Therefore, the scope of protection of this disclosure should be based on the scope of protection of the claims.

Claims

1.A method performed by a third node in a wireless communication system, the method comprising:receiving a first message from a second node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, andtransmitting a second message to the second node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node,wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.2.The method of claim 1, wherein the first message further includes at least one of:fourth information for requesting configuration of the target cell for the handover of the first node;fifth information for requesting configuration of a candidate cell for the handover of the first node.3.The method of claim 1, whereinthe first resource request information includes at least one of:resource request indication information, identification information of the base station, identification information of a distributed unit, identification information of a cell, information on the number of users served, carrier indication information, a preamble signal index, synchronization signal index information, a physical random access channel mask index;the fourth information includes at least one of:identification information of the target cell;first resource configuration information, which is used for generating configuration information related to measuring the candidate cell in the target cell by the third node,the fifth information includes at least one of:information related to layer 1 / layer 2 triggered mobility (LTM) handover;first configuration identification information, which is used to identify configuration corresponding to the candidate cell;identification information of a first candidate cell, which is used for identifying the candidate cell for the handover of the first node;second resource configuration information, which is used for generating configuration information related to measuring other candidate cells in the candidate cell for the handover of the first node by the third node;second resource request information for requesting resources of the third node.4.The method of claim 1, wherein the third information includes at least one of:identification information of a second candidate cell, which is used to identify a candidate cell accepted or not accepted by the third node;second configuration identification information, which is used to identify configuration corresponding to the candidate cell accepted or not accepted by the third node;first user identification information, which is information related to an identification used when the first node accesses the base station where the cell is located;sixth information, including configuration of the candidate cell accepted or not accepted by the third node;first configuration request information, which is used to request the second node to provide configuration information of the candidate cell identified by the identification information of the second candidate cell or the second configuration identification information.5.The method of claim 1, wherein the second message further includes at least one of:seventh information related to configuration of the target cell for the handover of the first node;eighth information related to configuration of a candidate cell for the handover of the first node.6.The method of claim 1, wherein the method further comprises:receiving a third message from the second node, wherein the third message includes ninth information related to a candidate cell accepted by the third node and / or tenth information related to a base station serving the candidate cell accepted by the third node.7.The method of claim 1, wherein the method further comprises:transmitting or receiving a fourth message to or from a fifth node serving the candidate cell, wherein the fourth message includes at least one of:second user identification information, including information related to identifying the first node on the third node and / or the fifth node;first release information, including information related to the one or more candidate cells allocated to the first node which needs to be released;first updated information, including information related to updated one or more candidate cells allocated to the first node.8.The method of claim 1, wherein the method further comprises:transmitting a fifth message to a fourth node, wherein the fifth message includes second update information including information related to updated one or more candidate cells allocated to the first node, wherein the fourth node is a distributed unit (DU) and the third node is a centralized unit (CU).9.The method of claim 1, wherein the first information, the sixth information, the eighth information or the ninth information, the first update information or the second update information further includes at least one of:third configuration identification information, which is used to identify configuration corresponding to the candidate cell;identification information of a third candidate cell, which is used for identifying a candidate cell configured to the first node;configuration information for a synchronization signal, including information related to configuration of the synchronization signal of the candidate cell;radio resource control (RRC) configuration information;thirteenth information, including information related to whether the RRC configuration information is a complete configuration;configuration information for synchronization, which is configuration information used to trigger the first node to acquire synchronization information of the candidate cell;configuration information for a beam, including information related to a beam used by the first node when transmitting a signal;resource configuration information of a reference signal, including information related to a resource of a reference signal of the candidate cell;first reset related configuration information, including information associated to determining reset related operations required by the third node when a cell of the first node changes;configuration information related to a first timing advance (TA) measurement;sharing indication information, wherein the indication information is shared by multiple user equipment;identification information of user equipment;identification information of a cell;a preamble signal index;carrier indication information indicating a carrier where the requested resource is located;a synchronization signal index;a physical random access channel mask index;information on usage time.10.The method of claim 9, wherein the configuration information for synchronization includes at least one of:configuration information related to a random access channel required for early synchronization;configuration information related to a RACH-less random access channel;configuration information related to early uplink synchronization;configuration information related to contention free random access;configuration information related to a random access channel.11.A method performed by a second node in a wireless communication system, the method comprising:transmitting a first message to a third node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, andreceiving a second message from the third node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node,wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.12.The method of claim 11, wherein the method further comprises:transmitting a sixth message to a fifth node, wherein the sixth message includes at least one of:third resource configuration information, which is used for generating configuration information related to measuring other candidate cells in the candidate cell by the fifth node;second release information, which is information related to the one or more candidate cells allocated to the first node which needs to be released;eleventh information, which is configuration information related to a base station serving the first node;twelfth information, which is information related to the one or more candidate cells allocated to the first node.13.The method of claim 12, wherein the eleventh information includes at least one of:identification information of a base station;identification information of a cell;third user identification information, which is information related to an identification used when the first node accesses the base station.14.The method of claim 11, wherein when the second node includes a centralized unit and a distributed unit, the method further comprises:the centralized unit of the second node receiving a third request message for requesting resources for transmitting a random access preamble signal transmitted by the distributed unit of the second node, andthe centralized unit of the second node transmitting a third response message for resource allocation to the distributed unit of the second node;the third request message includes at least one of the following: identification information of a cell, carrier indication information and synchronization signal index information; andthe third response message includes at least one of the following: a preamble signal index and a physical random access channel mask index.15.An apparatus in a wireless communication system, comprising:a transceiver; anda controller coupled with the transceiver and configured to:receive a first message from a second node, wherein the first message includes first information related to one or more candidate cells configured to a first node and / or second information related to a base station serving the one or more candidate cells, and / or first resource request information for requesting resources, andtransmitting a second message to the second node, wherein the second message includes third information related to that the third node accepts or doesn't accept the one or more candidate cells configured to the first node,wherein the first message is used for requesting to prepare a target cell or a candidate cell for handover of the first node.

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