Method performed by node in a wireless communication system and node therefore

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. According to one aspect of the present disclosure, there is provided a method for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) performed by a target master node (MN) in a wireless communication system, comprising: transmitting, by the target MN, a first message to a target secondary node (SN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM); and receiving, by the target MN from the target SN, a second message as a response to the first message, wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).

Description

METHOD PERFORMED BY NODE IN A WIRELESS COMMUNICATION SYSTEM AND NODE THEREFORE

[0001] The disclosure relates to wireless communication technology, and in particular to methods performed by nodes in a wireless communication system when a UE is in a mobility situation and each node.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] 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".

[0009] 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.

[0010] In order to reduce the delay of user equipment handover, the Layer 1 / Layer 2 Triggered Mobility (Layer 1 / Layer 2 Triggered Mobility: LTM) handover method uses underlying signaling to trigger the handover of user equipment. However, in this handover method, multiple different candidate cells need to be configured for the user equipment, which results in increased signaling overhead. Therefore, how to reduce the signaling overhead of LTM, especially in dual connectivity scenarios, is an urgent problem that needs to be solved.

[0011] The present disclosure relates to a method performed by a node in a wireless communication system and node.

[0012] Embodiments of the present disclosure provide a network node, a method performed by the node, a network node, and a node. The technical solutions provided by the embodiments of the present disclosure are as follows:

[0013] An embodiment of the present disclosure provides a method for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) performed by a target master node (MN) in a wireless communication system, comprising: transmitting, by the target MN, a first message to a target secondary node (SN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM); and receiving, by the target MN from the target SN, a second message as a response to the first message, wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).

[0014] An embodiment of the present disclosure provides a target master node (MN) for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) in a wireless communication system, comprising: a transceiver; and one or more processors coupled with the transceiver and configured to: transmit a first message to a target secondary node (SN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM), and receive, from the target SN, a second message as a response to the first message, wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).

[0015] An embodiment of the present disclosure provides a method for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) performed by a target secondary node (SN) in a wireless communication system, comprising: receiving, by the target SN, a first message from a target master node (MN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM); and transmitting, by the target SN to the target MN, a second message as a response to the first message, wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).

[0016] An embodiment of the present disclosure provides a target secondary node (SN) for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) in a wireless communication system, comprising: a transceiver; and one or more processors coupled with the transceiver and configured to: receive a first message from a target master node (MN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM), and transmit, to the target MN, a second message as a response to the first message, wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).

[0017] An embodiment of the present disclosure provides a method performed by a second node in a wireless communication system, including:

[0018] determining reference configuration information for configuring a secondary cell group of user equipment,

[0019] transmitting a second message to a first node, wherein the second message is used to provide configuration information of the user equipment;

[0020] wherein the second message includes at least one of: identification information of first user equipment, the reference configuration information of the secondary cell group, first indication information used to indicate release of the secondary cell group, first delta configuration information indicating user equipment configuration;

[0021] wherein the user equipment is configured as dual connectivity.

[0022] According to an embodiment of the present disclosure, the method further includes receiving a first message transmitted by the first node, wherein the first message is used to prepare the configuration information of the user equipment, and the first message includes at least one of:

[0023] identification information of second user equipment;

[0024] second indication information for indicating a usage of the first message;

[0025] third indication information for indicating to request a reference configuration;

[0026] first reference configuration information; and

[0027] assistant information for generating the reference configuration.

[0028] According to an embodiment of the present disclosure, it further includes that the determining the reference configuration information for configuring the secondary cell group of the user equipment is determined based on the first message.

[0029] According to an embodiment of the present disclosure, the first node and the second node are respectively the following nodes:

[0030] a source master node serving the user equipment and a source secondary node serving the user equipment; or

[0031] a source master node serving the user equipment and a candidate master node serving the user equipment; or

[0032] a candidate master node serving the user equipment and a source secondary node serving the user equipment.

[0033] According to an embodiment of the present disclosure, wherein the second message further includes at least one of: a reference configuration of a master cell group, a reference configuration of a primary cell, a reference configuration of a primary secondary cell, and a reference configuration of all cells.

[0034] According to an embodiment of the present disclosure, wherein the identification information of the second user equipment includes first identification information allocated by the first node and second identification information allocated by the source secondary node serving the user equipment;

[0035] The second indication information can be used to indicate at least one of the following types of handover: layer 3 handover, layer 1 / layer 2 triggered mobility (LTM), intra-base station handover, intra-base station LTM, intra-base station-central unit LTM, intra-base station master cell group LTM, intra-base station-central unit master cell group LTM, intra-base station handover, inter-base station LTM, inter-base station-central unit LTM, inter-base station master cell group LTM, inter-base station-central unit master cell group LTM, handover without secondary node change, LTM without secondary node change, master cell group LTM without secondary node change, intra-base station LTM without secondary node change, intra-base station-central unit master cell group LTM without secondary node change, inter-base station LTM without secondary node change, inter-base station-central unit LTM without secondary node change, inter-base station master cell group LTM without secondary node change, inter-base station-central unit master cell group LTM without secondary node change, LTM without primary secondary cell change, master cell group LTM without primary secondary cell change, intra-base station LTM without primary secondary cell change, intra-base station-central unit LTM without primary secondary cell change, intra-base station master cell group LTM without primary secondary cell change, intra-base station-central unit master cell group LTM without primary secondary cell change, inter-base station LTM without primary secondary cell change, inter-base station-central unit LTM without primary secondary cell change, inter-base station master cell group LTM without primary secondary cell change, inter-base station-central unit master cell group LTM without primary secondary cell change;

[0036] The third indication information includes at least one of the following information: request indication information for a reference configuration of a master cell group, request indication information for a reference configuration of a secondary cell group, request indication information for a reference configuration of all cell groups, request indication information for a reference configuration of a primary cell, request indication information for a reference configuration of a primary secondary cell, request indication information for a reference configuration of all cells;

[0037] The first reference configuration information includes at least one of the following information: a reference configuration of a master cell group, a reference configuration of a secondary cell group, a reference configuration of a primary cell, a reference configuration of a primary secondary cell, a reference configuration of all cells, identification information of a cell, identification information of a node;

[0038] The assistant information includes at least one of the following information: identification information of one or more target cells, identification information of one or more candidate cells, configuration information of a master cell group where a target cell is located, configuration information of a secondary cell where a target cell is located, configuration information of a master cell group where a candidate cell is located, configuration information of a secondary cell group where a candidate cell is located, configuration information of a master cell group where a serving cell is located, configuration information of a secondary cell group where a serving cell is located.

[0039] Embodiments of the present disclosure also provide a method performed by a first node in a wireless communication system, comprising:

[0040] transmitting a first message to a second node, wherein the first message is used to prepare configuration information of user equipment,

[0041] receiving a second message from a second node, wherein the second message is used to provide the configuration information of the user equipment;

[0042] wherein the second message includes at least one of: identification information of first user equipment, the reference configuration information of the secondary cell group, first indication information used to indicate release of the secondary cell group, first delta configuration information indicating user equipment configuration;

[0043] wherein the user equipment is configured as dual connectivity.

[0044] According to an embodiment of the present disclosure, wherein the first message includes at least one of: identification information of second user equipment; second indication information for indicating a usage of the first message; third indication information for indicating to request a reference configuration; first reference configuration information; and assistant information for generating the reference configuration.

[0045] According to an embodiment of the present disclosure, wherein the first node and the second node are respectively the following nodes: a source master node serving the user equipment and a source secondary node serving the user equipment; or a source master node serving the user equipment and a candidate master node serving the user equipment; or a candidate master node serving the user equipment and a source secondary node serving the user equipment.

[0046] According to an embodiment of the present disclosure, wherein the second message further includes at least one of: a reference configuration of a master cell group, a reference configuration of a primary cell, a reference configuration of a primary secondary cell, and a reference configuration of all cells.

[0047] According to an embodiment of the present disclosure, wherein the identification information of the second user equipment includes first identification information allocated by the first node and second identification information allocated by the source secondary node serving the user equipment;

[0048] The second indication information can be used to indicate at least one of the following types of handover: layer 3 handover, layer 1 / layer 2 triggered mobility (LTM), intra-base station handover, intra-base station LTM, intra-base station-central unit LTM, intra-base station master cell group LTM, intra-base station-central unit master cell group LTM, intra-base station handover, inter-base station LTM, inter-base station-central unit LTM, inter-base station master cell group LTM, inter-base station-central unit master cell group LTM, handover without secondary node change, LTM without secondary node change, master cell group LTM without secondary node change, intra-base station LTM without secondary node change, intra-base station-central unit master cell group LTM without secondary node change, inter-base station LTM without secondary node change, inter-base station-central unit LTM without secondary node change, inter-base station master cell group LTM without secondary node change, inter-base station-central unit master cell group LTM without secondary node change, LTM without primary secondary cell change, master cell group LTM without primary secondary cell change, intra-base station LTM without primary secondary cell change, intra-base station-central unit LTM without primary secondary cell change, intra-base station master cell group LTM without primary secondary cell change, intra-base station-central unit master cell group LTM without primary secondary cell change, inter-base station LTM without primary secondary cell change, inter-base station-central unit LTM without primary secondary cell change, inter-base station master cell group LTM without primary secondary cell change, inter-base station-central unit master cell group LTM without primary secondary cell change;

[0049] The third indication information includes at least one of the following information: request indication information for a reference configuration of a master cell group, request indication information for a reference configuration of a secondary cell group, request indication information for a reference configuration of all cell groups, request indication information for a reference configuration of a primary cell, request indication information for a reference configuration of a primary secondary cell, request indication information for a reference configuration of all cells;

[0050] The first reference configuration information includes at least one of the following information: a reference configuration of a master cell group, a reference configuration of a secondary cell group, a reference configuration of a primary cell, a reference configuration of a primary secondary cell, a reference configuration of all cells, identification information of a cell, identification information of a node;

[0051] The assistant information includes at least one of the following information: identification information of one or more target cells, identification information of one or more candidate cells, configuration information of a master cell group where a target cell is located, configuration information of a secondary cell where a target cell is located, configuration information of a master cell group where a candidate cell is located, configuration information of a secondary cell group where a candidate cell is located, configuration information of a master cell group where a serving cell is located, configuration information of a secondary cell group where a serving cell is located.

[0052] Embodiments of the present disclosure also provide a first node or a second node in a wireless communication system, comprising: a a transceiver configured to transmit and receive signals; and a controller coupled with the transceiver and configured to perform a method as previously described as performed by the corresponding first node or second node.

[0053] The present disclosure provides an efficient method performed by a node in a wireless communication system and node.

[0054] Figure 1 is an exemplary system architecture of a system architecture evolution in accordance with the present disclosure.

[0055] Figure 2 is an exemplary system architecture in accordance with various embodiments of the present disclosure.

[0056] Figure 3 is an exemplary flowchart of a method for obtaining a reference configuration between nodes according to various embodiments of the present disclosure.

[0057] Figure 4 is an exemplary flow diagram of a mechanism for requesting a reference configuration of a secondary cell group by a source master node from a source secondary node in accordance with the present disclosure.

[0058] Figure 5 is an exemplary flowchart of a mechanism for requesting a reference configuration of a secondary cell group by a source master node from a candidate master node in accordance with the present disclosure.

[0059] Figure 6 is an exemplary flow diagram of a mechanism for requesting a reference configuration of a secondary cell group by a candidate master node from a source secondary node in accordance with the present disclosure.

[0060] Figure 7 is an exemplary flowchart of a mechanism for providing a reference configuration of a secondary cell group by a source secondary node itself in accordance with the present disclosure.

[0061] Figure 8 illustrates an exemplary structure of various nodes suitable for use in the present disclosure.

[0062] Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms "transmit," "receive," and "communicate," as well as derivatives thereof, encompass both direct and indirect communication. The terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation. The term "or" is inclusive, meaning and / or. The phrase "associated with," as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term "controller" means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, "at least one of: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0063] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A "non-transitory" computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0064] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.

[0065] The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of various embodiments of the present 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 of the present disclosure. In addition, for the sake of clarity and conciseness, descriptions of well-known functions and structures may be omitted. In the present 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.

[0066] 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 present disclosure. Therefore, it should be obvious to those skilled in the art that the following descriptions of various embodiments of the present disclosure are provided for illustration usages only and are not intended to limit the usages of the present disclosure as defined in the appended claims and their equivalents.

[0067] 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.

[0068] 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 present 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.

[0069] The term "or" used in various embodiments of the present disclosure includes any of the listed terms and all combinations thereof. For example, "a or b" may include a, may include b, or may include both a and b.

[0070] 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.

[0071] Figures discussed below and various embodiments for describing the principles of the present 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 present disclosure can be implemented in any suitably arranged system or device.

[0072] Fig. 1 is an exemplary system architecture 1000 of system architecture evolution (SAE). User equipment (UE) 1001 is a terminal device for receiving data. An evolved universal terrestrial radio access network (E-UTRAN) 1002 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) 1003 is responsible for managing mobility context, session context and security information of the UE. A serving gateway (SGW) 1004 mainly provides functions of user plane, and the MME 1003 and the SGW 1004 may be in the same physical entity. A packet data network gateway (PGW) 1005 is responsible for functions of charging, lawful interception, etc., and may be in the same physical entity as the SGW 1004. A policy and charging rules function entity (PCRF) 1006 provides quality of service (QoS) policies and charging criteria. A serving general packet radio service support node (SGSN) 1008 is a network node device that provides routing for data transmission in a universal mobile telecommunications system (UMTS). A home subscriber server (HSS)1009 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.

[0073] Fig. 2 is an exemplary system architecture 2000 according to various embodiments of the present disclosure. Other embodiments of the system architecture 2000 can be used without departing from the scope of the present disclosure. User equipment (UE) 2001 is a terminal device for receiving data. A next generation radio access network (NG-RAN) 2002 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) 2003 is responsible for managing mobility context and security information of the UE. A user plane function entity (UPF) 2004 mainly provides functions of user plane. A session management function entity SMF 2005 is responsible for session management. A data network (DN) 2006 includes, for example, services of operators, access of Internet and service of third parties.

[0074] For convenience of description, the following description of the embodiments of the present disclosure involves dedicated names and explanations as follows:

[0075] 1. LTM (L1 / L2 Triggered Mobility): Layer 1 / Layer 2 triggered mobility.

[0076] 2. SCPAC (subsequent CPAC, Subsequent Conditional PSCell Addition or Change): Continuous (or subsequent) conditional primary secondary cell addition or change. After PSCell addition (or adding), PSCell change (or changing), primary cell (PCell) change or secondary cell group (SCG) release, based on subsequent CPAC configuration of the pre-configured candidate PSCell without reconfiguring and restarting conditional PSCell Change (CPC) and / or conditional PSCell Addition (CPA), a conditional PSCell addition procedure or a PSCell change (or changing) procedure is performed.

[0077] 3. CHO (Conditional Handover): Conditional Handover, for example, the handover process is performed only when the evaluation condition is met. The network side pre-configures the resources of multiple candidate cells (wherein the multiple candidate cells may be located in the same base station or in different base stations) based on the measurement report of the UE, and transmits the corresponding resources and measurement configurations of each candidate cell to the UE in advance., the UE saves the corresponding resources of each candidate cell and performs measurements for condition evaluation. When a candidate cell is found to meet the conditions, UE leaves the source cell, and applies the corresponding configuration after successfully accessing the candidate cell (for example, target cell) that meets the conditions. The UE then releases all configurations of other candidate cells, while the base station (or node) to which the target cell belongs informs the source base station (or node) which candidate cell was selected. The network side then performs an operation of releasing all configurations of other candidate cells.

[0078] 4. AMF (Access and Mobility Management Function): The Access and Mobility Management Function is a network element of the 5G core network and is responsible for 5G base station access and mobility management. 5G base station and AMF are connected through the NG-C interface.

[0079] 5. NG-RAN (New Generation Radio Access Network) node: next generation radio access network node, for example, 5G base station, including gNB or ng-eNB.

[0080] 6. gNB (next Generation Node B): next generation base station node, for example, 5G NR (New Radio) base station.

[0081] 7. gNB-DU (Distributed Unit): gNB Distributed Unit, gNB-DU has Radio Link Control (RLC) protocol, Medium Access Control (MAC) and Physical Layer (PHY) protocol and other functions.

[0082] 8. gNB-CU (Central Unit): gNB central unit, gNB-CU has Radio Resource Control RRC), Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) and other functions.

[0083] 9. NR-DC (NR-NR Dual Connectivity): New Radio-New Radio Dual Connectivity, or Next Generation Radio Access Network Dual Connectivity.

[0084] 10. MN (Master Node): A master node.

[0085] 11. SN (Secondary Node): A secondary node.

[0086] 12. MCG (Master cell group): A master cell group. In MR-DC, a group of serving cells associated with the Master Node, comprising of the SpCell (PCell) and optionally one or more SCells.

[0087] 13. SCG (Secondary Cell Group): A secondary Cell Group. In MR-DC, a group of serving cells associated with the Secondary Node, comprising of the SpCell (PSCell) and optionally one or more SCells.

[0088] 14. SpCell: a primary cell of a master or secondary cell group.

[0089] 15. SpCell: a special cell, e.g. a primary cell serving the UE, a primary cell of a master or secondary cell group.

[0090] 16. PSCell: a primary Secondary Cell, e.g. SpCell of a secondary cell group.

[0091] 17. PCell: a primary cell, e.g. SpCell of a master cell group.

[0092] 18. MR-DC (Multi-Radio Dual Connectivity): Dual connectivity between a E-UTRA node and a NR node, or between a NR node and a NR node.

[0093] It should be understood that the message names in this disclosure are only examples and other names may be used. The information that needs to be transmitted between interfaces can be defined separately in the form of new messages, or you can use the existing corresponding interface specifications to add new information elements (IE) to existing messages.

[0094] The exemplary embodiments of the present disclosure are further described below in conjunction with the accompanying drawings.

[0095] The text and drawings of this disclosure are provided as examples only to assist in understanding the present disclosure. They should not be construed as limiting the scope of the disclosure in any way. Although certain embodiments and examples have been provided, it will be apparent to those skilled in the art, based upon this disclosure, that changes can be made to the embodiments and examples shown without departing from the scope of the disclosure.

[0096] The entities and / or nodes described in this disclosure may include network entities or network logical units such as gNB, gNB Central Unit (gNB-CU), gNB Distributed Unit (gNB-DU), gNB-CU-Control Plane (gNB CU-CP), gNB-CU-User Plane (gNB CU-UP), en-gNB, eNB, ng-eNB, UE, Access and Mobility Management Function (AMF), Session Management Function (SMF), Mobility Management Entity (MME), etc.

[0097] The signal strength and / or signal quality in this disclosure may be a Received Signal Strength Indicator (RSSI), a Reference Signal Receiving Power (RSRP), a Reference Signal Receiving Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), etc.

[0098] The handover described in this disclosure may include one or more of the following: handover, secondary node addition, secondary node change, master node change, etc.

[0099] In this disclosure, the node may refer to a node or a cell managed by a node.

[0100] In this disclosure, the cell may refer to a cell or a node where a cell is located.

[0101] In this disclosure, the source node may refer to any source node in handover, such as source node, source secondary node, source master node, etc.

[0102] In this disclosure, a target node may also refer to a candidate target secondary node.

[0103] In this disclosure, a target node may refer to any target node in handover, such as a target node, a target secondary node, a target master node, a candidate target node, a candidate target secondary node, a candidate target master node, etc.

[0104] In this disclosure, the target node may refer to one or more of the following: target gNB CU, target gNB DU, target gNB CU-CP, target gNB CU-UP, etc.

[0105] In this disclosure, the source node may refer to one or more of the following: source gNB CU, source gNB DU, source gNB CU-CP, source gNB CU-UP, etc.

[0106] In this disclosure, master node and master base station are equivalent, secondary node and secondary base station are equivalent, source node and source base station are equivalent, target node and target base station are equivalent, candidate node and candidate base station are equivalent, source master node and source master base station are equivalent, target master node and target master base station are equivalent, candidate master node and candidate master base station are equivalent, source secondary node and source secondary base station are equivalent, target secondary node and target secondary base station are equivalent, candidate secondary node and candidate secondary base station are equivalent.

[0107] The message names in the disclosure are only examples, and other message names can be used.

[0108] The "first" and "second" included in the message name of the disclosure are only used to distinguish one message from another, and do not represent the execution or transmission order.

[0109] Detailed description of steps irrelevant to the disclosure is omitted in the present invention.

[0110] In the disclosure, the steps in each procedure can be executed in combination with each other or independently. The execution steps of each process are only examples, and other possible execution steps and / or orders are not excluded.

[0111] In the disclosure, 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), RAN nodes or other types of access nodes.

[0112] Nodes involved in this disclosure include:

[0113] First node: a base station, or a central unit of a base station, or a control plane part of a central unit of a base station. The base station can be a source base station, a target base station or a candidate base station, a source master base station, or a target master base station or a candidate master base station;

[0114] Second node: a base station, or a central unit of a base station, or a control plane part of a central unit of a base station. The base station can be a source secondary base station or a target secondary base station, or a target base station or a candidate base station.

[0115] The first node or the second node can be one of the following types (other types that can be used for user terminal access are not excluded):

[0116] - Long Term Evolution (LTE) base station;

[0117] - 5G base station;

[0118] - 6G base station;

[0119] - RAN node;

[0120] - Non-Terrestrial Networks (NTN) base station;

[0121] - High Altitude Platform Station (HAPS) base station;

[0122] - Drone base station; and

[0123] - WIFI access point.

[0124] In a dual connectivity configuration, the user equipment is served by a source master node and a source secondary node. In order to prepare candidate cells for LTM, the source node may transmit a request to other nodes (target master node, target node, or candidate master node, or candidate node) for LTM candidate cell preparation. Furthermore, the other node will further configure dual connectivity for the user, that is, after the user equipment hands over to the prepared candidate cell, it can still be in the configuration of dual connectivity. In such a scenario, when configuring candidate cells for the user equipment, the source master node will configure the configuration of one or more candidate cells for the user equipment, and the configuration of each candidate cell may also include the configuration of the secondary cell group (i.e., the configuration of the cell group served by the secondary node). In this way, the signaling overhead of the configuration increases. Therefore, how to reduce the signaling overhead of the configuration is an urgent problem to be solved. In order to achieve this, the present invention considers configuring a reference configuration and a delta configuration for user equipment, and then the user equipment can combine the reference configuration and the delta configuration to generate a complete configuration. In one implementation, the network side can configure a reference configuration for the user and one or more delta configurations, each delta configuration being for a different cell (such as different candidate cells, different candidate primary cells, different primary secondary cell), so that the user equipment can generate configuration information for each cell based on the reference configuration and each delta configuration. In one example, the reference configuration includes configured all configuration information of the user. In one embodiment, the reference configuration is information contained in Radio Resource Control (RRC) Reconfiguration information, such as configuration information of radio bearer, configuration information of Cell Group, configuration information of Radio link control (RLC) bearer, etc. For details, please refer to the information in the RRCReconfiguration message in 3GPP TS38.331. The delta configuration also includes the information contained in the Radio Resource Control (RRC) Reconfiguration information, but the information contained in the delta configuration will be determined based on the information configured to the user equipment. If the information configured to the user equipment is already in the reference configuration, the delta configuration does not need to contain the information. If the information configured to the user equipment is not in the reference configuration, or is different from the information in the reference configuration, the delta configuration will contain the information. Through this method, when the user equipment is to be provided with configuration information of multiple cells, the signaling overhead of configuring the user equipment can be reduced through the method of reference configuration plus multiple delta configurations. When the user equipment is in dual connectivity, both the master cell group and the secondary cell group have corresponding reference configurations.

[0125] In order to realize the signaling overhead of configuring user equipment, further, the present invention proposes a method for obtaining reference configuration between nodes to reduce the signaling overhead of configuring user equipment. The content of the embodiment in Figure 3 includes:

[0126] Step 1-1 (S1-1): The first node transmits a first message 100 to a second node, the message is used to request the reference configuration of the secondary cell group, or provide the reference configuration of the secondary cell group, and the reference configuration is configured to the user equipment, so that the user equipment can use it to generate the configuration of the secondary cell group to reduce the signaling overhead for configuring the user equipment. The beneficial effect of this message is to: request to configure the reference configuration of the user and reduce signaling overhead. The first message includes at least one of the following information:

[0127] > identification of user equipment, the information is used to identify the user equipment, and the information includes at least one of the following information:

[0128] >> first identification information, which is allocated by the first node, such as the identification used by the interface (such as Xn) between base stations allocated by the first node, such as UE XnAP ID (User Equipment Xn Application Protocol Identification).

[0129] >> second identification information, which is allocated by other nodes (nodes different from the first node). In one example, during the preparation process of the target cell or candidate cell, if the first node is the node where the target cell or candidate cell is located, and the first node decides to continue to configure the secondary node currently configured to the user equipment as the secondary node of the user equipment, that is, the second node is the secondary node, and the identification information is the identification information allocated by the source node serving the user equipment. For example, the identification used by the interface (Xn) between base stations allocated by the source node, such as Source node UE XnAP ID (source node user equipment Xn application protocol identification). The beneficial effect of this information is: helping the second node identify the user equipment it serves and determine whether to generate a reference configuration based on this information, and reducing the signaling for configuring the user equipment.

[0130] > usage indication information, which is used to indicate the usage of transmitting the above-mentioned first message. The beneficial effect of this information is: determining the handover type, and then determining the signaling for configuring the user, and reducing signaling overhead. This information can be used to indicate at least one of the following usages (the following usages can also be considered as types of handover, so the indication information can also be handover type indication information):

[0131] >> Handover, e.g. Layer 3 handover

[0132] >> LTM, or Master cell group LTM (MCG LTM)

[0133] >> CHO

[0134] >> Intra-base station handover (or intra-base station-central unit handover). In this type of handover, the prepared candidate cell (or target cell) and the serving cell of the user equipment are in the same base station or in the central unit of the same base station, and further, the indication information may also indicate one of the following handover types: intra-BS LTM, intra-BS-CU LTM, intra-BS MCG LTM, intra-BS-CU MCG LTM;

[0135] >> Inter-base station handover (or inter-base station-central unit handover). In this type of handover, the prepared candidate cell (or target cell) and the serving cell of the user equipment are in different base stations or in central units of different base stations. Further, the indication information may also indicate one of the following handover types: inter-BS LTM, inter-BS-CU LTM, inter-BS MCG LTM, inter-BS-CU MCG LTM;

[0136] >> Handover without secondary node change (or handover without primary secondary cell (PSCell) change). In this type of handover, the secondary node or PSCell serving the user equipment is not changed, but the candidate cell (or target cell) prepared for the user equipment and the serving cell (or source cell) of the user equipment may belong to different or the same base station or central unit of base stations. Further, this type of handover can also include any of the following types (that is, the indication information can also indicate one of the following handover types): LTM without SN change, MCG LTM without SN change, intra-BS LTM without SN change, intra-BS-CU LTM without SN change, intra-BS-CU LTM without SN change, intra-BS MCG LTM without SN change, intra-BS MCG LTM without SN change, intra-BS-CU MCG LTM without SN change, inter-BS LTM without SN change, inter-BS-CU LTM without SN change, inter-BS MCG LTM without SN change, inter-BS-CU MCG LTM without SN change, LTM without PSCell change, MCG LTM without PSCell change, intra-BS LTM without PSCell change, intra-BS-CU LTM without PSCell change, intra-BS MCG LTM without PSCell change, intra-BS-CU MCG LTM without PSCell change, inter-BS LTM without PSCell change, inter-BS-CU LTM without PSCell change, inter-BS MCG LTM without PSCell change, inter-BS-CU MCG LTM without PSCell change;

[0137] > request indication information for a reference configuration, which is used to indicate a request for a reference configuration (such as a reference configuration of a master cell group, a reference configuration of a secondary cell group, the reference configuration of the master cell group and the secondary cell group, a reference configuration of all cell groups). The beneficial effect of this information is to obtain the reference configuration and reduce the signaling for configuring the user equipment. After receiving this information, the second node will determine whether to provide the requested reference configuration, or determine whether it needs to request other nodes to provide the reference configuration. Further, the indication information may also include at least one of the following information:

[0138] >> request indication information for a reference configuration of a master cell group, which is used to indicate a request for a reference configuration of a master cell group.

[0139] >> request indication information for a reference configuration of a secondary cell group, which is used to indicate a request for a reference configuration of the secondary cell group.

[0140] >> request indication information for a reference configuration of all cell groups, which is used to indicate a request for a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0141] >> request indication information for a reference configuration of a primary cell (PCell), which is used to indicate a request for a reference configuration of the primary cell (PCell).

[0142] >> request indication information for a reference configuration of a primary secondary cell (PSCell), which is used to indicate a request for a reference configuration of a primary secondary cell (PSCell).

[0143] >> request indication information for a reference configuration of all cells, which is used to indicate a request for reference configuration of a primary cell (PCell), a reference configuration of a primary secondary cell (PSCell), and a reference configuration of a Secondary Cell (SCell).

[0144] > first reference configuration information, which contains the reference configuration used to configure the user equipment. Based on this information, the network node (such as the above-mentioned second node or other network nodes different from the first node and the second node) can generate the delta configuration information for configuring the user equipment based on this information, and transmit both the delta configuration information and the reference configuration information to the user equipment, then the user equipment can generate a complete configuration information based on the reference configuration information and the delta configuration information. The beneficial effect of this information is: reducing the signaling overhead of configuring user equipment by generating user configuration information based on the reference configuration. The reference configuration information includes at least one of the following information:

[0145] >> a reference configuration of a master cell group, which includes a reference configuration of the master cell group.

[0146] >> a reference configuration of a secondary cell group, which includes a reference configuration of the secondary cell group.

[0147] >> a reference configuration of a primary cell (PCell), which includes a reference configuration of the primary cell (PCell).

[0148] >> a reference configuration of a primary secondary cell (PSCell), which includes a reference configuration of a primary secondary cell (PSCell).

[0149] >> a reference configuration of all cells, which includes a reference configuration of a primary cell (PCell), a reference configuration of a primary secondary cell (PSCell), and a reference configuration of Secondary Cell (SCell).

[0150] >> identification information of a cell. In one example, the information is the identification information of the PCell, which identifies a PCell corresponding to the reference configuration of the master cell group or the reference configuration of a primary cell (PCell). In another example, the information is the identification information of the PSCell, which identifies the PSCell corresponding to the reference configuration of the secondary cell group or the reference configuration of a primary secondary cell (PSCell).

[0151] >> identification information of a node. In one example, the information is the identification information of the master node, which identifies the master node corresponding to the reference configuration of the master cell group or the reference configuration of the primary cell (PCell). In another example, the information is identification information of the secondary node, which identifies the secondary node corresponding to the reference configuration of the secondary cell group or the reference configuration of a primary secondary cell (PSCell).

[0152] > assistant information, which assists the second node to generate reference configuration information. After receiving the information, the second node will refer to the information to generate reference configuration information (such as a reference configuration of a master cell group, a reference configuration of a secondary cell group). The beneficial effect of this information is that a suitable reference configuration is generated based on the assistant information, reducing the information to configure the user equipment. The information includes at least one of the following:

[0153] >> identification information of one or more target cells. The target cells can be PCell or PSCell.

[0154] >> identification information of one or more candidate cells. The candidate cells can be an LTM candidate cell or a CHO candidate cell, and the candidate cell can also be a PCell or a PSCell.

[0155] >> configuration information of a master cell group where a target cell is located. The information is respectively given for the above-mentioned one or more target cells.

[0156] >> configuration information of a secondary cell where a target cell is located. The information is respectively given for the above-mentioned one or more target cells.

[0157] >> configuration information of a master cell group where a candidate cell is located. The information is respectively given for the above-mentioned one or more candidate cells.

[0158] >> configuration information of a secondary cell group where a candidate cell is located. The information is respectively given for the above-mentioned one or more candidate cells.

[0159] >> configuration information of a master cell group where a serving cell is located. The serving cell is a primary cell currently serving the user equipment.

[0160] >> configuration information of a secondary cell group where a serving cell is located. The serving cell is a primary secondary cell currently serving the user equipment.

[0161] Step 1-2 (S1-2): The second node transmits a second message 101 to the first node, the message uses to generate configuration information for configuring the user equipment, and the second message includes at least one of the following information:

[0162] > identification of user equipment. The information is used to identify the user equipment, and the information includes at least one of the following information:

[0163] >> first identification information, which is allocated by the first node, such as the identification used by the interface (such as Xn) between base stations allocated by the first node, such as UE XnAP ID (User Equipment Xn Application Protocol Identification).

[0164] >> second identification information, which is allocated by other nodes (nodes different from the first node). In one example, during the preparation process of the target cell or candidate cell, if the first node is the node where the target cell or candidate cell is located, and the first node decides to continue to configure the secondary node currently configured to the user equipment as the secondary node of the user equipment, that is, the second node is the secondary node, and the identification information is the identification information allocated by the source secondary node (because the source secondary node and the second node are the same node, the identification information is the identification information allocated by the source secondary node when the source secondary node and the source master node jointly serve the user equipment), for example, the identification used by the interface (Xn) (such as the interface between the source secondary node and the source master node) between base stations allocated by the source secondary node, such as Source secondary node UE XnAP ID (source secondary node user equipment Xn application protocol identification).

[0165] >> identification information of a source secondary node, which is used to indicate the source secondary node serving the user equipment.

[0166] > indication information for secondary cell group release, which indicates that the secondary cell group serving the user equipment is released or the secondary cell group is not configured for the user equipment. After receiving this information, the first node may not transmit reference configuration information of the secondary cell group to the user equipment. The beneficial effect of this information is to determine the configuration of the secondary cell group and reduce the signaling overhead of configuring the user equipment.

[0167] > second reference configuration information, which contains the reference configuration used to configure the user equipment. Based on this information, the network node (such as the first node, or other nodes different from the first node) will configure the reference configuration information to the user equipment. This information includes at least one of the following information:

[0168] >> a reference configuration of a master cell group, which includes a reference configuration of the master cell group.

[0169] >> a reference configuration of a secondary cell group, which includes a reference configuration of the secondary cell group.

[0170] >> a reference configuration of a primary cell (PCell), which includes a reference configuration of the primary cell (PCell).

[0171] >> a reference configuration of a primary secondary cell (PSCell), which includes a reference configuration of a primary secondary cell (PSCell).

[0172] >> a reference configuration of all cells, which includes a reference configuration of a primary cell (PCell), a reference configuration of a primary secondary cell (PSCell), and a reference configuration of Secondary Cell (SCell).

[0173] > first delta configuration information, which helps the user equipment generate a complete configuration. In one example, the delta configuration information can be combined with the above-mentioned "second reference configuration information" to generate a complete configuration. This information includes at least one of the following information. kind:

[0174] >> delta configuration of a master cell group, which includes delta configuration of the master cell group.

[0175] >> delta configuration of a secondary cell group, which includes delta configuration of the secondary cell group.

[0176] >> delta configuration of a primary cell (PCell), which includes delta configuration of the primary cell (PCell).

[0177] >> delta configuration of a primary secondary cell (PSCell), which includes delta configuration of a primary secondary cell (PSCell).

[0178] >> delta configuration of all cells, which includes delta configuration of a primary cell (PCell), delta configuration of a primary secondary cell (PSCell), and delta configuration of a secondary Cell (SCell).

[0179] When the above-mentioned first node is the source master node, it further includes: the first node transmitting a first configuration message to the user equipment, where the first configuration message includes the reference configuration information of the master cell group and the reference configuration information of the secondary cell group;

[0180] When the first node is not the source master node, it further includes: the first node transmitting (directly transmitting or transmitting through other nodes) the reference configuration information of the master cell group and / or the reference configuration information of the secondary cell group to the source master node, and then the source master node transmitting a first configuration message to the user equipment, wherein the first configuration message includes the reference configuration information of the master cell group and the reference configuration information of the secondary cell group.

[0181] Different implementations of the above process are introduced below based on the scenario of the master cell group LTM without secondary node change. The nodes involved in this scenario include the following nodes:

[0182] > Source master node: a base station of the PCell currently serving the user equipment

[0183] > Source secondary node: a base station of the PSCell currently serving the user equipment

[0184] > Candidate master node (or target master node): a serving base station of a candidate primary cell (PCell) or a serving base station of a target primary cell prepared for user equipment

[0185] > Candidate secondary node (or target secondary node): a serving base station of a candidate primary secondary cell (PSCell) or a serving base station of a target primary secondary cell prepared for the user equipment. Further, for the scenario of the master cell group LTM without secondary node change, because during the process of preparing the candidate cell or target cell, the secondary node serving the user equipment has not changed (that is, if the user equipment hands over to the candidate cell, the above-mentioned source secondary node are still the secondary node serving user equipment. i.e. the candidate or target secondary node is the same as the source secondary node), but the PSCell serving the user equipment may or may not change.

[0186] In the following embodiments, since it is considered that the candidate secondary node or the target secondary node is the same as the source secondary node, the "source secondary node" is used to represent the base station of the secondary cell group serving the user equipment. Further, in the following embodiments, the information contained in each message may refer to the above-mentioned first message and / or second message.

[0187] Embodiment 1: The reference configuration of the secondary cell group is requested by the source master node from the source secondary node.

[0188] As shown in Figure 4, this embodiment includes the following steps:

[0189] Step a-1 (Sa-1): The source master node transmits a first request message (such as a secondary node (SN) modification request message) to the source secondary node, wherein the first request message is used to request the reference configuration of the secondary cell group, and the message includes the following information at least one of:

[0190] > identification of user equipment, referring to the above first message.

[0191] > usage indication information, referring to the above first message. The source secondary node can determine based on this information that the source master node requests the reference configuration information of the secondary cell group. In one example, when the usage indication information indicates "handover without secondary node change" (or the type included in the above "handover without secondary node change"), the source secondary node can decide whether it is necessary to generate a reference configuration of the secondary cell group.

[0192] > request indication information for a reference configuration, referring to the above-mentioned first message. The source secondary node can determine based on the information that the source master base station requests the reference configuration information of the secondary cell group.

[0193] > assistant information, referring to the above-mentioned first message. The source secondary base station generates reference configuration information of the secondary cell group based on the information.

[0194] Step a-2 (Sa-2): The source secondary node transmits a first response message (such as a secondary node (SN) modification response message) to the source master node. The message provides the reference configuration information of the secondary cell group, and the message includes at least one of the following information:

[0195] > identification of user equipment, referring to the above second message.

[0196] > second reference configuration information, referring to the above second message. In one example, this information includes the reference configuration information of the secondary cell group.

[0197] Step a-3 (Sa-3): The source master node transmits a second request message (such as a Handover request message) to the candidate master node, the message is used to request to prepare the candidate cell for handover, such as LTM, and the message contains at least one of the following information:

[0198] > user identification information of a secondary node, which is identification information allocated by the source secondary node, such as SN UE XnAP ID.

[0199] > identification information of a secondary node, which is identification information of a source secondary node.

[0200] > usage indication information, referring to the above first message.

[0201] > request information for a reference configuration, referring to the above-mentioned first message. In one example, this information can be used to request the reference configuration of the master cell group.

[0202] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the master cell group, or to provide the reference configuration of the secondary cell group obtained in the above steps.

[0203] Step a-4 (Sa-4): The candidate master node transmits a third request message (such as a secondary node(SN) addition request message) to the source secondary node, and the message is used to request the addition of a secondary node serving the user equipment. The message containing at least one of the following information:

[0204] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0205] > user identification information of a second secondary node, which is the identification information allocated by the source secondary node, such as SN UE XnAP ID. Further, the allocated identification information is allocated to the user equipment when the source master node and the source secondary node serve the user equipment. After receiving the information, the source secondary node learns that the user equipment targeted by the third request message is the user equipment served by the source secondary node, and provides the reference configuration of the secondary cell group to the source master node in the above steps. Therefore, the source secondary node generates a delta configuration of the secondary cell group based on the reference configuration of the secondary cell group, and provides it to the candidate master base station in subsequent steps.

[0206] > usage indication information, referring to the above first message.

[0207] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the secondary cell group obtained in the above steps.

[0208] Step a-5 (Sa-5): The source secondary node transmits a third response message (such as a secondary node (SN) addition response message) to the candidate master node, and the message is used to provide configuration information of the secondary node serving the user equipment. The message containing at least one of the following information:

[0209] > first user identification information, which is identification information allocated by the candidate master base station, such as MN UE XnAP ID.

[0210] > third user identification information, which is identification information allocated by the secondary node, such as SN UE XnAP ID.

[0211] > first delta configuration information, referring to the above-mentioned second message. This information includes delta configuration of the secondary cell group. This configuration can be combined with the reference configuration of the secondary cell group to obtain the configuration of the secondary cell group.

[0212] Step a-6 (Sa-6): The candidate master node transmits a second response message (such as a Handover Request Acknowledge message) to the source master node, which contains the configuration of the master cell group (delta configuration) and the configuration of the secondary cell group (or delta configuration). If the secondary cell group is not configured, the message may also include indication information for secondary cell group release.

[0213] In the above embodiment, the secondary node will determine whether to generate a delta configuration information based on the secondary cell group based on the received UE identification information of the source secondary node transmitted from the candidate master node (such as the above-mentioned "user identification information of a second secondary node").

[0214] Embodiment 2: The reference configuration of the secondary cell group is requested by the source master node from the candidate master node.

[0215] As shown in Figure 5, this implementation includes the following steps:

[0216] Step b-1 (Sb-1): The source master node transmits a second request message (such as a Handover request message) to the candidate master node, the message is used to request the candidate cell to prepare for handover, such as LTM, the message contains at least one of the following information:

[0217] > user identification information of a secondary node, which is identification information allocated by the source secondary node, such as SN UE XnAP ID.

[0218] > identification information of a secondary node, which is identification information of a source secondary node.

[0219] > usage indication information, referring to the above first message.

[0220] > Request information for a reference configuration, referring to the above-mentioned first message. In one example, this information can be used to request the reference configuration of the secondary cell group. In another example, this information can be used to request the reference configuration of the master cell group and the reference configuration of the secondary cell group.

[0221] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the master cell group, or to provide the reference configuration of the secondary cell group, or to provide the reference configuration of the master cell group and the reference configuration of the secondary cell group.

[0222] Based on the different configurations of the above " request information for a reference configuration" and "first reference configuration information", there may be the following possible situations:

[0223] > providing a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0224] > requesting a reference configuration of a master cell group and providing a reference configuration of a secondary cell group.

[0225] > providing a reference configuration of a master cell group and requesting a reference configuration of a secondary cell group.

[0226] > requesting a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0227] Step b-2 (Sb-2): The candidate master node transmits a third request message (such as a secondary node (SN) addition request message) to the source secondary node, the message being used to request the addition of a secondary node serving the user equipment, the message containing at least one of the following information:

[0228] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0229] > user identification information of a second secondary node, which is the identification information allocated by the source secondary node, such as SN UE XnAP ID. Further, the allocated identification information is allocated to the user equipment when the source master node and the source secondary node serve the user equipment. After receiving this information, the source secondary node knows whether the reference configuration of the secondary cell group is provided (if it is provided to the candidate master node), and if it is, the source secondary node will generate the delta configuration of the secondary cell group based on the reference configuration of the secondary cell group.

[0230] > usage indication information, referring to the above first message. This information can also be used to implicitly indicate to request the reference configuration of the secondary cell group.

[0231] > request information for a reference configuration, referring to the above-mentioned first message. In one example, this information can be used to request the reference configuration of the secondary cell group.

[0232] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the secondary cell group.

[0233] Step b-3 (Sb-3): The source secondary node transmits a third response message (such as a secondary node (SN) addition response message) to the candidate master node, and the message is used to provide configuration information of the source secondary node serving the user equipment. The message contains at least one of the following information:

[0234] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0235] > third user identification information, which is identification information allocated by the source secondary node, such as SN UE XnAP ID.

[0236] > second reference configuration information, referring to the above second message. The information is generated by the source secondary node.

[0237] > first delta configuration information, referring to the above-mentioned second message. This information includes delta configuration of the secondary cell group. This configuration can be combined with the reference configuration of the secondary cell group to obtain the configuration of the secondary cell group.

[0238] Step b-4 (Sb-4): The candidate master node transmits a second response message (such as Handover Request Acknowledge message) to the source master node, and the message contains at least one of the following information:

[0239] > a configuration (or delta configuration) of a master cell group.

[0240] > a reference configuration of a master cell group. If it requested by the source master node in the above steps, this information is included.

[0241] > a configuration (or delta configuration) of a secondary cell group.

[0242] > a reference configuration of a secondary cell group. If it requested by the source master node in the above steps, this information is included.

[0243] > indication information for secondary cell group release, referring to the above second message.

[0244] In the above embodiment, the candidate master node re-requests the reference configuration of the secondary cell group from the source secondary node based on the request of the source master node, and the reference configuration of the secondary cell is transmitted by the source secondary node to the candidate master node, and then transmitted by the candidate master node to source master node.

[0245] Embodiment 3: The reference configuration of the secondary cell group is requested by the candidate master node from the source secondary node.

[0246] As shown in Figure 6, this implementation includes the following steps:

[0247] Step c-1 (Sc-1): The source master node transmits a second request message (such as a Handover request message) to the candidate master node, and the message is used to request to prepare the candidate cell for handover, such as LTM. The message contains at least one of the following information:

[0248] > user identification information of a secondary node, which is identification information allocated by the source secondary node, such as SN UE XnAP ID.

[0249] > identification information of a secondary node, which is identification information of a source secondary node.

[0250] > usage indication information, referring to the above first message.

[0251] > request information for a reference configuration, referring to the above-mentioned first message. In one example, this information can be used to request the reference configuration of the master cell group. In another example, this information can be used to request the reference configuration of the master cell group and the reference configuration of the secondary cell group.

[0252] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the master cell group, or to provide the reference configuration of the secondary cell group, or to provide the reference configuration of the master cell group and the reference configuration of the secondary cell group.

[0253] Based on the different configurations of the above " request information for a reference configuration" and "first reference configuration information", there may be the following possible situations:

[0254] > providing a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0255] requesting a reference configuration of a master cell group and providing a reference configuration of a secondary cell group.

[0256] > providing a reference configuration of a master cell group.

[0257] > requesting a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0258] Step c-2 (Sc-2): The candidate master node transmits a third request message (such as a secondary node (SN) addition request message) to the source secondary node, and the message is used to request the addition of a secondary node serving the user equipment. The message containing at least one of the following information:

[0259] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0260] > user identification information of a second secondary node, which is the identification information allocated by the source secondary node, such as SN UE XnAP ID. Further, the allocated identification information is allocated to the user equipment when the source master node and the source secondary node serve the user equipment. After receiving this information, the source secondary node knows whether the reference configuration of the secondary cell group is provided (if it is provided to the candidate master base station), and if it is, the source secondary node will generate the delta configuration of the secondary cell group based on the reference configuration of the secondary cell group.

[0261] > usage indication information, referring to the above first message. This information can also be used to implicitly indicate to request the reference configuration of the secondary cell group. In one example, when the usage indication information indicates "handover without secondary node change" (or the type included in the above "handover without secondary node change"), the source secondary node can decide whether it is necessary to generate a reference configuration of the secondary cell group.

[0262] > Request information for a reference configuration, referring to the above-mentioned first message. In one example, this information can be used to request the reference configuration of the secondary cell group.

[0263] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the secondary cell group.

[0264] Step c-3 (Sc-3): The source secondary node transmits a third response message (such as a secondary node (SN) addition response message) to the candidate master node, and the message is used to provide configuration information of the secondary node serving the user equipment. The message containing at least one of the following information:

[0265] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0266] > third user identification information, which is identification information allocated by the secondary node, such as SN UE XnAP ID.

[0267] > second reference configuration information, referring to the above second message. The information is generated by the source secondary node.

[0268] > first delta configuration information, referring to the above second message. In one example, the information includes the delta configuration of the secondary cell group. This configuration can be combined with the reference configuration of the secondary cell group to obtain a complete configuration of the secondary cell group.

[0269] Step c-4 (Sc-4): The candidate master base station transmits a second response message (such as a Handover Request Acknowledge message) to the source master base station. The message contains at least one of the following information:

[0270] > a configuration (or delta configuration) of a master cell group.

[0271] > a reference configuration of a master cell group. If it requested by the source master base station in the above steps, this information is included.

[0272] > a configuration (or delta configuration) of a secondary cell group.

[0273] > a reference configuration of a secondary cell group. If it requested by the source master base station in the above steps, this information is included.

[0274] > indication information for secondary cell group release, referring to the above second message.

[0275] In the above embodiment, the source secondary node transmits the reference configuration of the secondary cell group based on the request received from the candidate master node, and generates the delta configuration of the secondary cell group based on the reference configuration.

[0276] Embodiment 4: The reference configuration of the secondary cell group is provided by the source secondary node itself.

[0277] As shown in Figure 7, this implementation includes the following steps:

[0278] Step d-1 (Sd-1): The source master node transmits a second request message (such as a Handover request message) to the candidate master node, and the message is used to request the candidate cell to prepare for handover, such as LTM. The message contains at least one of the following information:

[0279] > user identification information of a secondary node, which is identification information allocated by the source secondary node, such as SN UE XnAP ID.

[0280] > identification information of a secondary node, which is identification information of a source secondary node.

[0281] > usage indication information, referring to the above first message.

[0282] > Request information for a reference configuration, referring to the above-mentioned first message. In one example, this information can be used to request the reference configuration of the master cell group. In another example, this information can be used to request the reference configuration of the master cell group and the reference configuration of the secondary cell group.

[0283] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the master cell group, or to provide the reference configuration of the secondary cell group, or to provide the reference configuration of the master cell group and the reference configuration of the secondary cell group.

[0284] Based on the different configurations of the above " request information for a reference configuration" and "first reference configuration information", there may be the following possible situations:

[0285] providing a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0286] requesting a reference configuration of a master cell group and providing a reference configuration of a secondary cell group.

[0287] providing a reference configuration of a master cell group.

[0288] requesting a reference configuration of a master cell group and a reference configuration of a secondary cell group.

[0289] Step d-2 (Sd-2): The candidate master node transmits a third request message (such as a secondary node (SN) addition request message) to the source secondary node, and the message is used to request the addition of a secondary node serving the user equipment. The message contains at least one of the following information:

[0290] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0291] > user identification information of a second secondary node, which is the identification information allocated by the source secondary node, such as SN UE XnAP ID. Further, the allocated identification information is allocated to the user equipment when the source master node and the source secondary node serve the user equipment. After receiving this information, the source secondary node knows whether the reference configuration of the secondary cell group is provided (if it is provided to the candidate master node), and if it is, the source secondary node will generate the delta configuration of the secondary cell group based on the reference configuration of the secondary cell group.

[0292] > usage indication information, referring to the above first message. In one example, this information can also be used to implicitly indicate to request the reference configuration of the secondary cell group. In another example, the secondary node can decide whether it is necessary to generate a reference configuration of the secondary cell based on this information. In another example, when the usage indication information indicates "handover without secondary node change" (or the type included in the above "handover without secondary node change"), the source secondary node can decide whether it is necessary to generate a reference configuration of the secondary cell group.

[0293] > first reference configuration information, referring to the above first message. In one example, this information can be used to provide the reference configuration of the secondary cell group.

[0294] Step d-3 (Sd-3): The source secondary node transmits a third response message (such as a secondary node (SN) addition response message) to the candidate master node, and the message is used to provide configuration information of the secondary node serving the user equipment. The message contains at least one of the following information:

[0295] > first user identification information, which is identification information allocated by the candidate master node, such as MN UE XnAP ID.

[0296] > third user identification information, which is identification information allocated by the secondary node, such as SN UE XnAP ID.

[0297] > second reference configuration information, referring to the above second message. In one example, this information includes the reference configuration information of the secondary cell group.

[0298] > first delta configuration information, referring to the above second message. In one example, the information includes the delta configuration of the secondary cell group. This configuration can be combined with the reference configuration of the secondary cell group to obtain a complete configuration of the secondary cell group.

[0299] Step d-4 (Sd-4): The candidate master node transmits a second response message (such as Handover Request Acknowledge message) to the source master node, the message containing at least one of the following information:

[0300] > a configuration (or delta configuration) of a master cell group.

[0301] > a reference configuration of a master cell group. If it is requested by the source master base station in the above steps, this information is included.

[0302] > a configuration (or delta configuration) of a secondary cell group.

[0303] > a reference configuration of a secondary cell group. If it requested by the source master base station in the above steps, this information is included.

[0304] > indication information for secondary cell group release, referring to the above second message.

[0305] Further, when the secondary node decides to provide the reference configuration of the secondary cell group, it can also transmit the reference configuration of the secondary cell group to the source master node by itself, such as

[0306] Step d-5 (Sd-5): The source secondary node transmits a fourth request message (such as secondary node (SN) modification required message) to the source master node. The message includes at least one of the following information:

[0307] > identification of user equipment, referring to the above second message.

[0308] > indication information for secondary cell group release, referring to the above second message.

[0309] > second reference configuration information, referring to the above second message.

[0310] In this embodiment, the secondary node autonomously decides whether it needs to generate a reference configuration of the secondary cell group. If necessary, it will transmit the reference configuration of the secondary cell group to the candidate master node, and then the candidate master node transmits it to the source master base station, or the secondary node directly transmits the reference configuration of the secondary cell group to the source master node.

[0311] Fig. 8 is a block diagram of a node (or a node apparatus) according to an example embodiment of the present disclosure. Here, the structure and function of a node are explained by taking it as an example, but it should be understood that the shown structure and function can also be applied to the base stations, the relay node and user equipment. Referring to Fig. 8, the node 800 includes a transceiver 810, a controller 820 and a memory 830. Under the control of the controller 820, which may be implemented as one or more processors, the node 800 (including the transceiver 810 and the memory 830) is configured to perform the operations of the node described herein. Although the transceiver 810, the controller 820 and the memory 830 are shown as separate entities, they may be implemented as a single entity, such as a single chip. The transceiver 810, the controller 820 and the memory 830 may be electrically connected or coupled to each other. The transceiver 810 can transmit and receive signals to and from other network entities, such as another node and / or UE. In one embodiment, the transceiver 810 may be omitted. In this case, the controller 820 may be configured to execute instructions (including computer programs) stored in the memory 830 to control the overall operation of the node 800, thereby realizing the operation of the node described herein.

[0312] According to some embodiments, the user equipment described in the present disclosure may include a cellular or other communication device having a single-line display or a multi-line display or a cellular or other communication device without a multi-line display; PCS (Personal Communications Service), which can combine voice, data processing, fax and / or data communication capabilities; PDA(Personal Digital Assistant), which can include RF receiver, pager, Internet / Intranet access, web browser, notepad, calendar and / or GPS(Global Positioning System) receiver; a conventional laptop and / or palmtop computer or other device having and / or including a radio frequency receiver. As used herein, "terminal" and "terminal device" can be portable, transportable, installed in vehicles (air, sea and / or land), or suitable and / or configured to operate locally, and / or operate in any other location on the earth and / or space in a distributed form. The "terminal" and "terminal device" used here can also be communication terminals, internet terminals and music / video playing terminals, such as PDA, MID (Mobile Internet Device) and / or a mobile phone with music / video playing function, and smart TV, set-top box and other devices.

[0313] Those skilled in the art can realize that the disclosure can be realized in other specific forms without changing the technical idea or basic features of the disclosure. Therefore, it should be understood that the above-mentioned embodiments are only examples and are not limited. The scope of the present disclosure is defined by the appended claims rather than by the detailed description. Therefore, it is to be understood that all modifications or changes derived from the meaning and scope of the appended claims and their equivalents are within the scope of this disclosure.

[0314] In the above embodiments of the present disclosure, all operations and messages may be selectively performed or may be omitted. Furthermore, the operations in each embodiment do not need to be performed sequentially, and the order of the operations can be changed. Messages do not need to be transmitted in order, and the transmission order of messages may change. Each operation and each message transfer can be performed independently.

[0315] Although the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.

Claims

A method for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) performed by a target master node (MN) in a wireless communication system, comprising:transmitting, by the target MN, a first message to a target secondary node (SN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM); andreceiving, by the target MN from the target SN, a second message as a response to the first message,wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).The method of claim 1, further comprisingreceiving, by the target MN from a source MN, a third message requesting preparation of the MCG LTM.The method of claim 2,wherein the identification information of the UE comprises UE Xn application protocol identification (UE XnAP ID) in the source MN.The method of claim 1,wherein the reference configuration information of the SCG is related to a delta configuration for configuring the UE.The method of claim 2, further comprising:transmitting, by the target MN to the source MN, a fourth message as a response to the third message.The method of claim 1, wherein the first message comprises a SN addition request message.The method of claim 2, wherein the third message comprises a handover request message.A target master node (MN) for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) in a wireless communication system, comprising:a transceiver; andone or more processors coupled with the transceiver and configured to:transmit a first message to a target secondary node (SN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM), andreceive, from the target SN, a second message as a response to the first message,wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).The target MN of claim 8, wherein the one or more processors are configured to:receive, from a source MN, a third message requesting preparation of the MCG LTM.The target MN of claim 9,wherein the identification information of the UE comprises UE Xn application protocol identification (UE XnAP ID) in the source MN.The target MN of claim 8,wherein the reference configuration information of the SCG is related to a delta configuration for configuring the UE.The target MN of claim 9, wherein the one or more processors are configured to:transmit, to the source MN, a fourth message as a response to the third message.The target MN of claim 8, wherein the first message comprises a SN addition request message.The target MN of claim 9, wherein the third message comprises a handover request message.A method for configuring a user equipment (UE) in mulita radio dual connectivity (MR-DC) performed by a target secondary node (SN) in a wireless communication system, comprising:receiving, by the target SN, a first message from a target master node (MN), wherein the first message is used to indicate master cell group (MCG) layer 1 / layer 2 triggered mobility (LTM); andtransmitting, by the target SN to the target MN, a second message as a response to the first message,wherein the first message comprises identification information of the UE and reference configuration information of a secondary cell group (SCG).

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