Network node and communication method

Abstract

The network node has a receiving unit that receives a message requesting LTM (Lower layer Triggered Mobility) from another network node, a control unit that decides which cell to set as an LTM candidate, and a transmitting unit that transmits a UE context setup request to a subordinate DU (Distributed Unit) based on the decision, the receiving unit receives a UE context setup response from the DU, and the transmitting unit transmits a response to the message to the other network node.

Description

Technical Field

[0001] This invention relates to network nodes and communication methods in communication systems. Background Technology

[0002] Within 3GPP (3rd Generation Partnership Project), research is underway on wireless communication technologies known as 5G or NR (New Radio) to further increase system capacity, improve data transmission speeds, and reduce latency within radio intervals. Within 5G, various wireless technologies are being researched to meet the requirement of achieving throughput exceeding 10Gbps while maintaining latency below 1ms within radio intervals.

[0003] In NR, a network architecture is being studied that includes 5GC (5G Core Network) corresponding to EPC (Evolved Packet Core) as the core network in the LTE (Long Term Evolution) network architecture, and NG-RAN (Next Generation Radio Access Network) corresponding to E-UTRAN (Evolved Universal Terrestrial Radio Access Network) as the RAN (Radio Access Network) in the LTE network architecture (e.g., Non-Patent Literature 1).

[0004] Furthermore, in version 19, as a mobility enhancement, it is anticipated that functional enhancements will be made to support the following scenario: LTM (Lower layer Triggered Mobility) will be performed while maintaining inter-CU (inter-Central Unit) LTM (Lower layer Triggered Mobility) and DC (Dual connectivity) (e.g., Non-Patent Document 2).

[0005] Existing technical documents

[0006] Non-patent literature

[0007] Non-patent literature 1: 3GPP TS 23.501 V18.4.0 (2023-12)

[0008] Non-Patent Document 2: 3GPP TSG-RAN Meeting #101 RP-232618, Bengaluru, India, 11-15 September 2023 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Currently, only intra-CU LTM is supported during non-DC periods, and intra-SN PSCell LTM (Intra Secondary Node Primary Secondary Cell LTM) during DC periods when the MN (Master Node) does not participate. On the other hand, signaling between CUs or between base stations in LTM during DC periods is not specified.

[0011] This invention was made in view of the above-mentioned problems, and its purpose is to expand the application scope of LTM (Lower layer Triggered Mobility) in order to enhance mobility.

[0012] Methods for solving problems

[0013] According to the disclosed technology, a network node is provided, comprising: a receiving unit for receiving a message requesting LTM (Lower layer Triggered Mobility) from other network nodes; a control unit for determining which cell to set as an LTM candidate; and a sending unit for sending a UE context setup request to subordinate DUs (Distributed Units) based on the decision, wherein the receiving unit receives a UE context setup response from the DU, and the sending unit sends a response to the message to the other network nodes.

[0014] Invention Effects

[0015] According to the publicly available technology, it is possible to expand the application scope of LTM (Lower layer Triggered Mobility) in order to enhance mobility. Attached Figure Description

[0016] Figure 1 This is a diagram used to illustrate an example of a communication system.

[0017] Figure 2This is a diagram illustrating an example of a communication system in a roaming environment.

[0018] Figure 3 This is a diagram illustrating an example of a system in an embodiment of the present invention.

[0019] Figure 4 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0020] Figure 5 This is a diagram illustrating an example of a system in an embodiment of the present invention.

[0021] Figure 6 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0022] Figure 7 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0023] Figure 8 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0024] Figure 9 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0025] Figure 10 This is a diagram illustrating an example of a system in an embodiment of the present invention.

[0026] Figure 11 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0027] Figure 12 This is a diagram illustrating an example of a system in an embodiment of the present invention.

[0028] Figure 13 This is a timing diagram used to illustrate an example of LTM in an embodiment of the present invention.

[0029] Figure 14 This is a diagram illustrating an example of the functional structure of the base station 10 and network node 30 in an embodiment of the present invention.

[0030] Figure 15 This is a diagram illustrating an example of the functional structure of terminal 20 in an embodiment of the present invention.

[0031] Figure 16 This is a diagram illustrating an example of the hardware structure of the base station 10 and the terminal 20 in an embodiment of the present invention.

[0032] Figure 17This is a diagram illustrating an example of the structure of a vehicle 2001 according to an embodiment of the present invention. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments described below are examples, and the application of the present invention is not limited to the following embodiments.

[0034] In the operation of the wireless communication system according to embodiments of the present invention, existing technologies may be appropriately used. However, such existing technologies include, but are not limited to, existing LTE. Furthermore, unless otherwise stated, the term "LTE" as used in this specification is intended to have a broad meaning that includes LTE-Advanced and later modes (e.g., NR) or wireless LAN (Local Area Network).

[0035] Furthermore, in embodiments of the present invention, the so-called "configuration" of wireless parameters can be either a pre-configured specific value or a wireless parameter notified from network node 30 or terminal 20.

[0036] Figure 1 This is a diagram used to illustrate an example of a communication system. For example... Figure 1 As shown, the communication system consists of a terminal 20, i.e., a UE, and multiple network nodes 30. Hereinafter, it is assumed that each function corresponds to one network node 30, but multiple functions can be implemented by one network node 30, or one function can be implemented by multiple network nodes 30. Furthermore, the term "connection" as used below can refer to either a logical connection or a physical connection.

[0037] The RAN (Radio Access Network) is a network node 30 with radio access capabilities, and may also include a base station 10, connected to the UE, AMF (Access and Mobility Management Function), and UPF (User Plane Function). The AMF is a network node 30 with functions such as RAN interface termination, NAS (Non-Access Stratum) termination, registration management, connection management, arrival management, and mobility management. The UPF is a network node 30 with functions such as PDU (Protocol Data Unit) session points, packet routing and forwarding, and user plane QoS (Quality of Service) handling, interconnected with the DN (Data Network). The UPF and DN constitute a network slice. In the wireless communication network of the embodiments of this invention, multiple network slices are constructed.

[0038] The AMF connects with the UE, RAN, SMF (Session Management function), NSSF (Network Slice Selection Function), NEF (Network Exposure Function), NRF (Network Repository Function), UDM (Unified Data Management), AUSF (Authentication Server Function), PCF (Policy Control Function), and AF (Application Function). AMF, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, and AF are interconnected network nodes 30 via interfaces based on their respective services: Namf, Nsmf, Nnssf, Nnef, Nnrf, Nudm, Nausf, Npcf, and Naf.

[0039] The SMF (Service Provider Function) is a network node 30 with functions such as session management, UE IP (Internet Protocol) address allocation and management, DHCP (Dynamic Host Configuration Protocol) function, ARP (Address Resolution Protocol) proxy, and roaming function. The NEF (Network Element Function) is a network node 30 with the ability to notify other NFs (Network Functions) and handle events. The NSSF (Network Slice Selection Assistance Information) is a network node 30 with functions such as selecting the network slice to which the UE connects, determining the allowed NSSAI (Network Slice Selection Assistance Information), determining the set NSSAI, and determining the AMF set to which the UE connects. The PCF (Public Network Function Function) is a network node 30 with the function of controlling network policies. The AF (Application Provider Function) is a network node 30 with the function of controlling application servers. The NRF (Network RF Service Function) is a network node 30 with the function of discovering NF instances that provide services. The UDM (User Data Repository) is a network node 30 that manages subscriber data and authentication data. The UDM is connected to the UDR (User Data Repository) that maintains this data.

[0040] Figure 2 This is a diagram illustrating an example of a communication system in a roaming environment. For example... Figure 2 As shown, the network consists of a terminal 20, i.e., a UE, and multiple network nodes 30. Hereinafter, it is assumed that each function corresponds to one network node 30, but multiple functions can be implemented by one network node 30, or one function can be implemented by multiple network nodes 30. Furthermore, the term "connection" as used below can refer to either a logical connection or a physical connection.

[0041] The RAN is a network node 30 with wireless access capabilities, connected to the UE, AMF, and UPF. The AMF is a network node 30 with functions such as RAN interface termination, NAS termination, registration management, connection management, arrival management, and mobility management. The UPF is a network node 30 with functions such as PDU session anchoring for external connections, packet routing and forwarding, and user plane QoS processing, interconnected with the DN. The UPF and DN constitute a network slice. In the wireless communication network of this embodiment, multiple network slices are constructed.

[0042] AMF connects to UE, RAN, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, AF, and SEPP (Security Edge Protection Proxy). AMF, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, and AF are network nodes 30 interconnected via interfaces based on their respective services, Namf, Nsmf, Nnssf, Nnef, Nnrf, Nudm, Nausf, Npcf, and Naf.

[0043] The SMF (Service Provider Function) is a network node 30 with functions such as session management, UE IP address allocation and management, DHCP function, ARP proxy, and roaming function. The NEF (Network Provider Function) is a network node 30 with the ability to notify other NFs and handle events. The NSSF (Network Provider Function) is a network node 30 with functions such as selecting the network slice to which the UE connects, determining allowed NSSAI (Network Service Access Control), determining configured NSSAI, and determining the AMF set to which the UE connects. The PCF (Network Service Function) is a network node 30 with the function of performing network policy control. The AF (Application Provider Function) is a network node 30 with the function of controlling application servers. The NRF (Network Provider Function) is a network node 30 with the function of discovering NF instances that provide services. The SEPP (Secure Provider Module) is a non-transparent proxy that filters control plane messages between PLMNs (Public Land Mobile Networks). Figure 2 The vSEPP shown is the SEPP in the visited network, and the hSEPP is the SEPP in the home network.

[0044] like Figure 2 As shown, the UE is in a roaming environment connected to the RAN and AMF in a VPLMN (Visited PLMN). The VPLMN and HPLMN (Home PLMN) are connected via vSEPP and hSEPP. The UE can, for example, communicate with the UDM of the HPLMN via the AMF of the VPLMN.

[0045] Furthermore, in NG-RAN (Next Generation Radio Access Network), the RAN node, i.e., gNB, can also have an architecture that separates gNB-CU (Central Unit) and gNB-DU (Distributed Unit). One gNB-CU can also accommodate multiple gNB-DUs, and one gNB-DU can also accommodate multiple cells.

[0046] In version 19, as a mobility enhancement, it is anticipated that functional enhancements will be made to support the following scenario: LTM (Lower layer Triggered Mobility) will be performed while maintaining inter-CU (inter-Central Unit) LTM (Lower layer Triggered Mobility) and DC (Dual connectivity) (e.g., Non-Patent Document 2).

[0047] Currently, only intra-CU LTM is supported during non-DC operations, and intra-SN PSCell LTM (Intra Secondary Node Primary Secondary Cell LTM) during DC operations where the MN (Master Node) does not participate. On the other hand, signaling between CUs or between base stations during DC operations is specified.

[0048] Therefore, the Xn signaling used in the overall LTM between CUs and the Xn signaling between MN-SNs in the LTM at DC can also be specified as follows.

[0049] In version 18 DU-LTM, the CU needs to obtain the following information from the DU.

[0050] • List of SSB index / CSI-RS index (obtained outside the LTM procedure)

[0051] • Target candidate cell ID

[0052] • Target candidate LTM configuration ID

[0053] • LTM configuration ID mapping list (a list of all candidate cell IDs and configuration IDs)

[0054] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0055] • PRACH resource (used for early RACH (early random access channel))

[0056] • Lower layer reference configuration

[0057] • Lower layer configuration (including CSI report configuration)

[0058] Therefore, the operations shown in 1)-4) below can also be performed.

[0059] 1) Inter-CU LTM target preparation

[0060] In version 18, information obtained by the CU from the DU via F1 signaling can also be obtained from the target gNB.

[0061] 2) DC Scenario 1 (SN-DU Switching) LTM Preparation

[0062] It is also possible to specify the process for setting up LTM in both MN-initiated and SN-initiated scenarios.

[0063] 3) DC Scenario 2 (MN-DU Switching) LTM Preparation

[0064] In order to maintain DC with SN after MN change, SN can also be added in advance by candidate MN during LTM target preparation.

[0065] 4) Conditional LTM preparation

[0066] In addition to the above, it is also possible to generate conditional LTM settings such as execution conditions.

[0067] Figure 3 This is a diagram illustrating an example of a system in an embodiment of the present invention. Figure 3 The diagram illustrates the LTM between CUs in a non-DC state. The UE moves from the source CU and source DU to the target CU and target DU. CUs are connected via XnAP, and CU-DUs are connected via F1AP. Other candidate DUs can also belong to the source CU and target CU.

[0068] The information required for the RRCReconfiguration used to generate the LTM from the source CU can also be the following.

[0069] • List of SSB indexes / CSI-RS indexes

[0070] • Target candidate cell ID

[0071] • LTM configuration ID mapping list (a list of all candidate cell IDs and configuration IDs)

[0072] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0073] • PRACH resource configuration (for early RACH)

[0074] • TCI state configuration

[0075] SSB Information

[0076] • Lower layer reference configuration

[0077] • Lower layer configuration (including CSI report configuration)

[0078] Among the above information, the information that the source CU needs to obtain through signaling may also be the following information.

[0079] • Target candidate cell ID

[0080] • PRACH resource configuration (for early RACH)

[0081] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0082] • TCI state configuration

[0083] SSB Information

[0084] • Lower layer reference configuration

[0085] • Lower layer configuration (including CSI report configuration)

[0086] The information mentioned above, which includes both the source CU indication and the target CU indication, can also be the following information.

[0087] The target candidate cell ID can also determine its own...

[0088] • PRACH resource configuration (used for early RACH) > Can also determine whether to perform early RACH.

[0089] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets) can also be determined itself.

[0090] • Lower layer reference configuration can also determine which layer will generate the reference.

[0091] Regarding candidates within a CU, the information that a source CU can generate in this device can also be the following information.

[0092] • List of SSB indexes / CSI-RS indexes

[0093] • Target candidate cell ID

[0094] • LTM configuration ID mapping list (a list of all candidate cell IDs and configuration IDs)

[0095] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0096] Regarding candidates within a CU, the information included in the source CU's indication in F1 signaling can also be the following.

[0097] • Target candidate cell ID

[0098] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0099] • Whether to perform early RACH / UE-based TA measurement

[0100] Which DU generates the reference configuration?

[0101] Regarding candidates within a CU, the information obtained by the source CU via F1 signaling can also be the following.

[0102] • PRACH resource configuration (for early RACH)

[0103] • TCI state configuration

[0104] SSB Information

[0105] • Lower layer reference configuration

[0106] • Lower layer configuration (including CSI report configuration)

[0107] Option 1: If the source CU issues an instruction to acquire all information, the information related to the candidates under the target CU can also be as follows.

[0108] The information that the source CU can generate in this device can also be the following information.

[0109] • List of SSB indexes / CSI-RS indexes

[0110] • Target candidate cell ID

[0111] • LTM configuration ID mapping list (a list of all candidate cell IDs and configuration IDs)

[0112] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0113] The information included in the source CU's instruction in the Xn signaling can also be the following.

[0114] • Target candidate cell ID

[0115] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0116] • Whether to perform early RACH / UE-based TA measurement

[0117] Which DU generates the reference configuration?

[0118] The information obtained by the source CU through Xn signaling can also be the following information.

[0119] • PRACH resource configuration (for early RACH)

[0120] • TCI state configuration

[0121] SSB Information

[0122] • Lower layer reference configuration

[0123] • Lower layer configuration (including CSI report configuration)

[0124] Option 2: If the target CU follows the request of the source CU to obtain instructions, the information related to the candidates under the target CU can also be as follows.

[0125] The information that the source CU can generate in this device can also be the following information.

[0126] • List of SSB indexes / CSI-RS indexes

[0127] • Target candidate cell ID

[0128] • LTM configuration ID mapping list (a list of all candidate cell IDs and configuration IDs)

[0129] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0130] The information included in the source CU's instruction in the Xn signaling can also be the following.

[0131] LTM has been initiated.

[0132] • The upper limit on the number of candidates that the target CU can generate

[0133] • Does the target CU generate a reference configuration?

[0134] The information determined by the target CU can also be the following information.

[0135] • Target candidate cell ID

[0136] • CSI resource configuration (a list of cell IDs and SSB / CSI-RS sets)

[0137] • Whether to perform early RACH / UE-based TA measurement

[0138] Which DU generates the reference configuration?

[0139] The information obtained by the source CU through Xn signaling can also be the following information.

[0140] • PRACH resource configuration (for early RACH)

[0141] • TCI state configuration

[0142] SSB Information

[0143] • Lower layer reference configuration

[0144] • Lower layer configuration (including CSI report configuration)

[0145] Figure 4 This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S101, the source CU determines the initiation of LTM (LTM initiation decision). In step S101, the source CU may also determine the following instruction items, which will be included in the LTM request or LTM update.

[0146] • Whether to execute LTM

[0147] • Whether the target CU's cells are included in the LTM candidate.

[0148] Which cell should be designated as an LTM candidate?

[0149] • CSI resource configuration

[0150] • It is also possible to decide whether to perform early RACH and / or UE-based TA measurements for each target cell or target CU.

[0151] • For nodes that generate reference configurations, it is also possible to determine whether to use an object DU or an object CU.

[0152] In step S102, the source CU sends a UE Context Setup (UE Context Setting) request to the source DU for other candidate UEs. In step S103, the source DU sends a response to the source CU. In step S104, the source CU sends an LTM Request (LTM Request) to the target CU.

[0153] In step S105, the target CU performs a configuration decision. In step S105, the target CU may also determine the following instruction items and instruct the subordinate DUs.

[0154] Which cell should be designated as an LTM candidate?

[0155] • CSI resource configuration

[0156] • It can also be determined whether to perform early RACH and / or UE-based TA measurements for each target cell.

[0157] • For nodes that generate reference configurations, the object DU can also be determined.

[0158] In step S106, the target CU sends a UE Context Setup Request to the target DU. In step S107, the target DU sends a UE Context Setup Response to the target CU. In step S108, the target CU sends an LTM Request Ack to the source CU. The target CU replies to the source CU with information obtained from the preparation performed on its subordinate candidate cells in steps S106 and S107.

[0159] In step S109, the source CU sends a source-oriented UE context change (UE Context Mod) to the source DU. In step S110, the source DU sends a response to the source CU.

[0160] In step S111, the source CU sends an LTM update to the target CU. In step S112, the target CU sends a UE context setup request to the target DU. In step S113, the target DU sends a UE context setup response to the target CU. In step S114, the target CU sends an LTM update acknowledgment to the source CU. In step S115, the source CU sends an RRCReconfiguration to the UE.

[0161] The following information can also be included in LTM request or LTM update messages.

[0162] • Whether to trigger LTM (indicator)

[0163] • Target candidate cell ID

[0164] • Source cell ID

[0165] • LTM configuration ID

[0166] • Other candidates list (a list of all candidates that includes the following information)

[0167] - Cell ID

[0168] -LTM configuration ID

[0169] - Node ID

[0170] -Lower layer configuration

[0171] -RACH configuration

[0172] -TCI state configuration list

[0173] • Indicator (signal) requesting the generation of lower layer reference configuration.

[0174] • Lower layer reference configuration

[0175] • CSI resource configuration (a list of cell IDs / configuration IDs and SSB / CSI-RS sets)

[0176] • Requests an indicator (indicator) for generating RACH configuration for early RACH.

[0177] • Request the use of UE-based TA measurements, or generate an indication (indicator) for this purpose.

[0178] • Node ID

[0179] The information described above can be contained as a single message or as a list of multiple messages. It can also be included as a standalone Information Element (IE) or within a list.

[0180] LTM request or LTM update messages can be either existing Xn messages (e.g., Handover Request) or new messages.

[0181] The node ID mentioned above can be either the ID of the source and / or target gNB / CU / DU in Xn and / or F1 (e.g., gNB-DUUE F1AP ID), or the ID of the node itself (e.g., Source gNB-DU ID, Global gNB ID).

[0182] Table 1 shows examples of information elements contained in LTM request or LTM update messages.

[0183]

[0184] The following information can also be included in the LTM request confirmation or LTM update confirmation message.

[0185] • An indication (indicator) to reject the triggering of LTM (which can also be sent via an LTM preparation failure message).

[0186] • Accepted target candidate cell ID

[0187] • Accepted LTM configuration ID

[0188] • Indicator (signal) requesting the generation of lower layer reference configuration.

[0189] • Lower layer reference configuration

[0190] • An indication of whether the lower layer configuration is full or delta.

[0191] • Accepted CSI resource configuration (a list of cell IDs / configuration IDs and SSB / CSI-RS sets)

[0192] • Acceptable SSB index or CSI-RS index

[0193] • SSB Information / CSI-RS Information (A list of information required to determine the SSB or CSI-RS)

[0194] • RACH configuration for early RACH

[0195] • Indicates whether UE-based TA measurements are used or a setting for this purpose.

[0196] • Node ID

[0197] The information above can be included as a single message or as a list of multiple messages. It can also be included as a standalone message or within a list.

[0198] The LTM request acknowledgment or LTM update acknowledgment message can be either an existing Xn message (e.g., a Handover Request Ack) or a new message.

[0199] The node ID mentioned above can be the ID of the source and / or target gNB / CU / DU in Xn and / or F1 (e.g., gNB-DUUE F1AP ID), or it can be the ID of the node itself (e.g., Source gNB-DU ID, Global gNB ID).

[0200] Table 2 shows examples of information elements contained in LTM request confirmation or LTM update confirmation messages.

[0201]

[0202] The IDs of the source and / or target gNB, CU, or DU in Xn and / or F1 (e.g., gNB-DU UE F1AP ID) can be included in the UE Context Setup, UE Context Modification Request, or Response messages, or the ID of the node itself (e.g., Source gNB-DU ID, Global gNB ID) can be included.

[0203] The information described above can be included as a single message or as a list of multiple messages. It can be included as a standalone message or within a list. It can be sent within existing F1 messages or as a new message.

[0204] Table 3 shows examples of information elements contained in the F1 signaling of UE Context Setup, UE ContextModification Request, or Response messages.

[0205]

[0206] Figure 5 This is a diagram illustrating an example of a system in an embodiment of the present invention. Figure 5 The diagram illustrates the LTM between CUs in DC state. The UE moves from the source SN-CU and source SN-DU to the target SN-CU and target SN-DU. Other candidate DUs can also belong to the source SN-CU and target SN-CU.

[0207] Figure 6 This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S201, the MN-CU determines the initiation of LTM (LTM initiation decision). In step S201, the MN-CU may also determine the following indication items and include them in the LTM request or LTM update to the SN.

[0208] • Whether to execute LTM

[0209] • Whether the target SN's cells are included in the LTM candidate.

[0210] Which cell should be designated as an LTM candidate?

[0211] • CSI resource configuration

[0212] • It is also possible to decide whether to perform early RACH and / or UE-based TA measurements for each target cell or target CU.

[0213] • For nodes that generate reference configurations, it is also possible to determine whether to use an object DU or an object CU.

[0214] In step S202, the MN-CU sends a UE Context Setup request to the MN-DU for other candidate UEs. In step S203, the MN-DU sends a response to the MN-CU. In step S204, the MN-CU sends an SN LTM Request to the target SN-CU (T-SNCU).

[0215] In step S205, the target SN-CU performs a configuration decision. In step S205, the target SN-CU may also determine the following instruction items and instruct the subordinate DUs.

[0216] Which cell should be designated as an LTM candidate?

[0217] • CSI resource configuration

[0218] • It can also be determined whether to perform early RACH and / or UE-based TA measurements for each target cell.

[0219] • For nodes that generate reference configurations, the object DU can also be determined.

[0220] In step S206, the target SN-CU sends a UE Context Setup Request to the target SN-DU. In step S207, the target SN-DU sends a UE Context Setup Response to the target SN-CU. In step S208, the target SN-CU sends an SN LTM Request Ack to the MN-CU. The target SN-CU may also reply to the MN-CU with information obtained from the preparations performed on its subordinate candidate cells in steps S206 and S207.

[0221] In step S209, the MN-CU sends a source-oriented UE context modification to the MN-DU. In step S210, the MN-DU sends a UE context modification response to the MN-CU.

[0222] In step S211, the MN-CU sends an SN LTM Update to the target SN-CU. In step S212, the target SN-CU sends a UE Context Setup Modification to the target SN-DU. In step S213, the target SN-DU sends a UE Context Modification Response to the target CU. In step S214, the target SN-CU sends an SN LTM Update Ack to the MN-CU.

[0223] The MN can also perform the same preparation process for the source SN as for the target SN. In step S215, the MN-CU sends an SN LTM Update to the source SN-CU. In step S216, the source SN-CU sends an SN LTM Request Ack to the MN-CU. In step S217a, the MN-CU sends an RRCReconfiguration to the UE. Alternatively, in step S217b, the source SN can also send an RRCReconfiguration to the UE. That is, the RRCReconfiguration to the UE can also be generated and sent in the MN or the source SN.

[0224] Figure 7 This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S301, the MN-CU determines the initiation of LTM (LTM initiation decision). In step S301, the MN-CU may also determine the following indication items, which will be included in the LTM request or LTM update to the SN.

[0225] • Whether to execute LTM

[0226] • Whether the target SN's cells are included in the LTM candidate.

[0227] Which cell should be designated as an LTM candidate?

[0228] • CSI resource configuration

[0229] • It is also possible to decide whether to perform early RACH and / or UE-based TA measurements for each target cell or target CU.

[0230] • For nodes that generate reference configurations, it is also possible to determine whether to use an object DU or an object CU.

[0231] In step S302, the MN-CU sends a UE Context Setup request to the MN-DU for other candidate UEs. In step S303, the MN-DU sends a response to the MN-CU. In step S204, the MN-CU sends an SN LTM Request to the source SN-CU (S-SN CU).

[0232] In step S305, the source SN can also perform the same preparation phase of the CU-to-LTM as in the non-DC case on the target SN. Alternatively, the result of this preparation phase can be included in the SN LTM request acknowledgment and sent to the MN. In step S306, the source SN-CU sends an SN LTM request acknowledgment (SN LTM Request Ack) to the MN-CU.

[0233] The MN can also perform the same preparation process as the target SN for the source SN. In step S307a, the MN-CU sends RRCReconfiguration to the UE. Alternatively, in step S307b, the source SN can also send RRCReconfiguration to the UE. That is, the RRCReconfiguration to the UE can also be generated and sent in the MN or the source SN.

[0234] Figure 8 This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S401, the source SN-CU determines the initiation of LTM (LTM initiation decision). In step S401, the source SN-CU may also determine the following instruction items, which are included in the SN LTM Required to MN.

[0235] • Whether to execute LTM

[0236] • Whether the target SN's cells are included in the LTM candidate.

[0237] Which cell should be designated as an LTM candidate?

[0238] • CSI resource configuration

[0239] • It is also possible to decide whether to perform early RACH and / or UE-based TA measurements for each target cell or target CU.

[0240] • For nodes that generate reference configurations, it is also possible to determine whether to use an object DU or an object CU.

[0241] In step S402, the source SN-CU sends the SN LTM Required to the MN-CU.

[0242] In step S403, MN can also perform the same as... Figure 6 or Figure 7 The same process can be used. Alternatively, the result of this process can be included in the required acknowledgment for the SN LTM and sent to the source SN.

[0243] In step S403, the MN-CU performs a configuration decision. In step S403, the MN-CU may also determine the following instruction items and provide instructions to the subordinate DU, source SN, and / or target SN.

[0244] Which cell should be designated as an LTM candidate?

[0245] • CSI resource configuration

[0246] • It can also be determined whether to perform early RACH and / or UE-based TA measurements for each target cell.

[0247] • For nodes that generate reference configurations, the object DU can also be determined.

[0248] In step S404, the MN-CU sends an SN LTM Required Ack to the source SN-CU. Additionally, in Figure 8 executed in Figure 6 In this process, step S215 can also be considered as step S404, in which case step S216 can also be omitted. Figure 8 In Figure 6 If the process is executed, step S404 can be omitted or executed before step S403.

[0249] The MN can also perform the same preparation process for the source SN as for the target SN. In step S405a, the MN-CU sends RRCReconfiguration to the UE. Alternatively, in step S405b, the source SN sends RRCReconfiguration to the UE. That is, the RRCReconfiguration to the UE can also be generated and sent in the MN or the source SN.

[0250] Figure 9 This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S501, the source SN-CU determines the initiation of LTM (LTM initiation decision). In step S501, the source SN-CU may also determine the following instruction items and include them in the SN LTM Required to MN.

[0251] • Whether to execute LTM

[0252] • Whether the target SN's cells are included in the LTM candidate.

[0253] Which cell should be designated as an LTM candidate?

[0254] • CSI resource configuration

[0255] • It is also possible to decide whether to perform early RACH and / or UE-based TA measurements for each target cell or target CU.

[0256] • For nodes that generate reference configurations, it is also possible to determine whether to use an object DU or an object CU.

[0257] In step S502, the source SN can also perform the same preparation phase of the CU-to-LTM as in the non-DC case on the target SN. Alternatively, the result of this preparation phase can be included in the SN LTM Required and sent to the MN. In step S503, the source SN-CU sends the SN LTM Required to the MN-CU. In step S504, the MN-CU sends the SN LTM Required Ack to the source SN-CU.

[0258] The MN can also perform the same preparation process as the target SN for the source SN. In step S505a, the MN-CU sends RRCReconfiguration to the UE. Alternatively, in step S505b, the source SN can also send RRCReconfiguration to the UE. That is, the RRCReconfiguration to the UE can also be generated and sent in the MN or the source SN.

[0259] The LTM request and LTM update messages mentioned above can also be replaced with SN LTM request, SN LTM update, and SNLTM required. That is, the IE contained in the LTM request and LTM update messages mentioned above can also be included in SN LTM request, SNLTM update, and SN LTM required.

[0260] The LTM request confirmation and LTM update confirmation messages mentioned above can also be replaced with SN LTM request confirmation, SN LTM update confirmation, and SN LTM required confirmation. That is, the IE contained in the LTM request confirmation and LTM update confirmation messages mentioned above can also be included in SN LTM request confirmation, SN LTM update confirmation, and SN LTM required confirmation.

[0261] The following can also be included in the SN LTM request, SNLTM update, and SN LTM required confirmation: RRCReconfiguration containing the low-level settings of MN.

[0262] Alternatively, the LTM update confirmation, SN LTM request confirmation, and SN LTM requirements may include: RRCReconfiguration containing the lower-level settings of SN.

[0263] The SN LTM request, SN LTM update, SN LTM request acknowledgment, and SN LTM update acknowledgment messages can be either existing Xn messages (e.g., SN Addition Request) or new messages.

[0264] The node ID can be either the ID of the source and / or target gNB / CU / DU in Xn and / or F1 (e.g., gNB-DU UEF1AP ID), or the ID of the node itself (e.g., source gNB-DU ID, global gNB ID). The node ID can also be the ID of the source or target MN or SN in Xn (e.g., M-NG-RAN node UE XnAP ID).

[0265] The message can include the ID of the source and / or target gNB / CU / DU in Xn and / or F1 (e.g., gNB-DU UE F1AP ID), or the ID of the node itself (e.g., Source gNB-DU ID, Global gNB ID). Furthermore, the message can also include the ID of the source or target MN or SN in Xn (e.g., M-NG-RAN node UE XnAP ID).

[0266] In addition to the above, it may also include the ID of the MN or SN of the source or destination in Xn (e.g., M-NG-RAN node UE XnAP ID (M-NG-RAN node UE XnAP ID)).

[0267] The information described above can be included as a single message or as a list of multiple messages. It can be included as a standalone message or within a list. It can be sent within existing F1 messages or as a new message.

[0268] Figure 10 This is a diagram illustrating an example of a system in an embodiment of the present invention. Figure 10 The diagram illustrates the LTM between CUs in DC state. The UE moves from the source MN-CU and source MN-DU to the target MN-CU and target MN-DU. Other candidate DUs can also belong to the source MN-CU and target MN-CU.

[0269] Figure 11This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S601, the source MN-CU determines the initiation of LTM (LTM initiation decision). In step S601, the source MN-CU may also determine the following indication items and include them in the LTM request or LTM update.

[0270] • Whether to execute LTM

[0271] • Whether the target SN's cells are included in the LTM candidate.

[0272] Which cell should be designated as an LTM candidate?

[0273] • CSI resource configuration

[0274] • It is also possible to decide whether to perform early RACH and / or UE-based TA measurements for each target cell or target CU.

[0275] • For nodes that generate reference configurations, it is also possible to determine whether to use an object DU or an object CU.

[0276] In step S602, the source MN-CU sends a UEContext Setup request to the source MN-DU for other candidates. In step S603, the source MN-DU sends a UEContextSetup Response to the MN-CU. In step S604, the source MN-CU sends an LTM Request to the target MN-CU (T-MN CU).

[0277] In step S605, the target MN-CU performs a configuration decision. In step S605, the target MN-CU may also determine the following instruction items and instruct the subordinate DUs.

[0278] Which cell should be designated as an LTM candidate?

[0279] • CSI resource configuration

[0280] • It can also be determined whether to perform early RACH and / or UE-based TA measurements for each target cell.

[0281] • For nodes that generate reference configurations, the object DU can also be determined.

[0282] In step S606, the target MN-CU sends a UE Context Setup Request to the target MN-DU. In step S607, the target MN-DU sends a UE Context Setup Response to the target MN-CU. In step S608, the target MN-CU sends an SN LTM Request Confirmation to the SN-CU. The target MN-CU may also send the information obtained from the preparation performed on its subordinate candidate cells in steps S606 and S607 to the SN-CU.

[0283] In step S609, the SN-CU sends an SN LTM Request Ack to the target MN-CU. In step S610, the target MN-CU sends an LTM Request Ack to the source MN-CU. In step S611, the source MN-CU sends a UE context change (UE Context SetupModification) to the source MN-DU. In step S612, the source MN-DU sends a UE context change response to the source MN-CU.

[0284] In step S613, the source MN-CU sends an LTM update to the target MN-CU. In step S614, the target MN-CU sends a UE context modification (UE context setup modification) to the target MN-DU. In step S615, the target MN-DU sends a UE context modification response to the target MN-CU. The target MN can also accept information from the SN that the source MN is currently executing a DC on, and perform DC setup preparation with that SN.

[0285] In step S616, the target MN-CU sends an LTM update acknowledgment (LTM Update Ack) to the source MN-CU. In step S617, the source MN-CU sends an RRCReconfiguration to the UE.

[0286] The source SN node ID can also be included in LTM requests and LTM updates. The RRCReconfiguration with the MN low-level configuration can also be included in SN LTM requests, SN LTM updates, and SN LTM required acknowledgments. The RRCReconfiguration with the SN low-level configuration can also be included in LTM update acknowledgments, SN LTM request acknowledgments, and SN LTM required acknowledgments.

[0287] The SN LTM Request, SN LTM Update, SN LTM Request Confirmation, and SN LTM Update Confirmation messages can be either existing Xn messages (e.g., SN Addition Request) or new messages.

[0288] The message can include the ID of the source and / or target gNB / CU / DU in Xn and / or F1 (e.g., gNB-DU UE F1AP ID), or the ID of the node itself (e.g., Source gNB-DU ID, Global gNB ID). Furthermore, the message can also include the ID of the source or target MN or SN in Xn (e.g., M-NG-RAN node UE XnAP ID).

[0289] The information described above can be included as a single message or as a list of multiple messages. It can be included as a standalone message or within a list. It can be sent within existing F1 messages or as a new message.

[0290] Figure 12 This is a diagram illustrating an example of a system in an embodiment of the present invention. Figure 12 The diagram illustrates the LTM between CUs in a non-DC state. The UE moves from the source CU and source DU to the target CU and target DU. CUs are connected via XnAP, and CU-DUs are connected via F1AP. Other candidate DUs can also belong to the source CU and target CU.

[0291] Figure 13This is a timing diagram illustrating an example of LTM in an embodiment of the present invention. In step S701, the source CU determines the initiation of LTM (LTM initiation decision). In step S701, the source CU may also determine the following indication items and include them in the LTM request or LTM update.

[0292] • Low-level settings of source cells and candidate cells under the source CU

[0293] • Execution conditions determined by the source CU

[0294] In step S702, the source CU sends a UE Context Setup request to the source DU for other candidate UEs. In step S703, the source DU sends a response to the source CU. In step S704, the source CU sends an LTM Request to the target CU.

[0295] In step S705, the target CU performs a configuration decision. In step S705, the target CU or its subordinate DUs can also determine the execution conditions for the conditional LTM of its candidate cells. These execution conditions may include: execution conditions for initial LTM cell handover, and a list of candidate IDs corresponding to the execution conditions for subsequent LTMs. These execution conditions can be determined by the source CU, a DU under the source CU, the target CU, or a DU under the target CU.

[0296] In step S706, the target CU sends a UE Context Setup Request to the target DU. In step S707, the target DU sends a UE Context Setup Response to the target CU. In step S708, the target CU sends an LTM Request Ack to the source CU.

[0297] In step S709, the source CU sends a source-oriented UE context change (UE Context Mod) to the source DU. In step S710, the source DU sends a response to the source CU.

[0298] In step S711, the source CU sends an LTM update to the target CU. In step S712, the target CU sends a UE context setup request to the target DU. In step S713, the target DU sends a UE context setup response to the target CU. In step S714, the target CU sends an LTM update acknowledgment to the source CU. In step S715, the source CU sends an RRC reconfiguration to the UE.

[0299] In addition to the information shown in Table 1 or Table 2, LTM request, LTM request confirmation, LTM update, or LTM update confirmation may include execution conditions for Conditional LTM for each candidate cell.

[0300] The execution conditions may also include: execution conditions for the initial LTM cell switch and a list of candidate IDs corresponding to the execution conditions for subsequent LTMs.

[0301] The information described above can be included as a standalone IE, sent as a container, or contained within a list. The messages can be existing Xn messages (e.g., Handover Request Ack) or new messages.

[0302] Table 4 shows examples of IE execution conditions.

[0303]

[0304] In addition to the information shown in Table 3, the UE context establishment, UE context change, or UE context response messages may also include execution conditions for Conditional LTM for each candidate cell.

[0305] The execution conditions may also include: execution conditions for initial LTM cell switch and a list of candidate IDs corresponding to the execution conditions for subsequent LTM.

[0306] The information described above can be included as a standalone IE, sent as a container, or included in certain lists. The messages described above can be existing F1 messages (e.g., UE ContextSetup Response) or new messages.

[0307] Table 5 shows examples of IE execution conditions.

[0308]

[0309] Through the above embodiments, it is possible to set LTM between CUs and LTM in DC, or conditional LTM, for the UE.

[0310] That is, it can expand the application scope of LTM (Lower layer Triggered Mobility) in order to enhance mobility.

[0311] (Device structure)

[0312] Next, an example of the functional structure of the base station 10, network node 30, and terminal 20 implementing the above-described processing and operation will be explained. The base station 10, network node 30, and terminal 20 include the functions of the embodiments described above. However, the base station 10, network node 30, and terminal 20 may also be configured to each possess only a portion of the functions described in the embodiments.

[0313] <Base station 10 and network node 30>

[0314] Figure 14 This is a diagram illustrating an example of the functional structure of base station 10 and network node 30. (See diagram for example.) Figure 14 As shown, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. Figure 14 The functional structure shown is only one example. The functional distinctions and names of the functional units can be arbitrary, as long as the operations involved in the embodiments of the present invention can be implemented. Furthermore, network node 30 may also have the same functional structure as base station 10. Moreover, network nodes 30 with multiple different functions in the system architecture may also be composed of multiple network nodes 30 separated according to each function.

[0315] The transmitting unit 110 includes the following functions: generating a signal to be transmitted to the terminal 20 or other network node 30, and transmitting the signal via wired or wireless means. The receiving unit 120 includes the following functions: receiving various signals transmitted from the terminal 20 or other network node 30, and obtaining, for example, higher-level information from the received signals. A communication unit including the transmitting unit 110 and the receiving unit 120 may also be configured.

[0316] The setting unit 130 stores the preset setting information and various setting information sent to the terminal 20 into the storage device, and reads them from the storage device as needed. The content of the setting information is, for example, information related to LTM.

[0317] The control unit 140 performs LTM-related processing as described in the embodiment. Furthermore, the control unit 140 performs processing related to communication with the terminal 20. The signal transmission-related functional units of the control unit 140 may also be included in the transmitting unit 110, and the signal reception-related functional units of the control unit 140 may be included in the receiving unit 120.

[0318] Terminal 20

[0319] Figure 15 This is a diagram illustrating an example of the functional structure of terminal 20. For example... Figure 15 As shown, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. Figure 15 The functional structure shown is only one example. The functional distinctions and names of the functional units can be arbitrary, as long as the operations involved in the embodiments of this invention can be implemented.

[0320] The transmitting unit 210 generates a transmitting signal based on the transmitting data and transmits the transmitting signal wirelessly. The receiving unit 220 wirelessly receives various signals and obtains higher-layer signals from the received physical layer signals. Furthermore, the receiving unit 220 has the following functions: receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, or reference signals, etc., transmitted from the network node 30. A communication unit including the transmitting unit 210 and the receiving unit 220 can also be configured.

[0321] The setting unit 230 stores various setting information received from the network node 30 via the receiving unit 220 into a storage device, and reads it from the storage device as needed. Furthermore, the setting unit 230 also stores preset setting information. The content of the setting information may include, for example, information related to LTM.

[0322] The control unit 240 performs the processing involved in LTM as described in the embodiment. Alternatively, the functional units related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and the functional units related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0323] (Hardware structure)

[0324] The block diagrams used in the description of the above embodiments ( Figure 14 as well as Figure 15 The diagram illustrates functional blocks. These functional blocks (structural units) are implemented through any combination of at least one of hardware and software. Furthermore, there are no particular limitations on the implementation method of each functional block. That is, each functional block can be implemented using a single device that is physically or logically combined, or by directly or indirectly (e.g., using wired, wireless, etc.) connecting two or more physically or logically separate devices, or by using multiple devices. Functional blocks can also be implemented by combining software with one or more of the aforementioned devices.

[0325] The functions include judgment, decision, determination, calculation, calculation, processing, export, investigation, search, confirmation, receiving, sending, output, access, resolution, selection, choosing, establishing, comparison, assumption, expectation, regard as, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning, but are not limited to these. For example, a functional block (structural unit) that implements the sending function is called a transmitting unit or transmitter. Each of these functions, as described above, is implemented without particular limitation in its method.

[0326] For example, in one embodiment of this disclosure, the network node 30, terminal 20, etc., can also function as a computer for processing the wireless communication method of this disclosure. Figure 16 This diagram illustrates an example of the hardware structure of the base station 10 and terminal 20 according to an embodiment of this disclosure. The network node 30 may also have the same hardware structure as the base station 10. The base station 10 and terminal 20 described above may also be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0327] Additionally, in the following description, the term "device" can be replaced with circuit, device, unit, etc. The hardware structure of base station 10 and terminal 20 can be configured as either including one or more of the devices shown in the figures, or as a device that does not include any of them.

[0328] Regarding the various functions in base station 10 and terminal 20, specific software (programs) are read into the hardware such as processor 1001 and storage device 1002, so that processor 1001 performs calculations and controls communication via communication device 1004, or controls at least one of reading out and writing data in storage device 1002 and auxiliary storage device 1003.

[0329] The processor 1001, for example, enables the operating system to operate and control the computer as a whole. The processor 1001 may also be a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic devices, registers, etc. For example, the control unit 140, control unit 240, etc., described above may also be implemented by the processor 1001.

[0330] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 to the storage device 1002, and performs various processes accordingly. As a program, a program that causes the computer to perform at least a portion of the operations described in the above embodiments can be used. For example, Figure 14 The control unit 140 of the base station 10 shown can also be implemented by a control program stored in the storage device 1002 and operated in the processor 1001. Furthermore, for example, Figure 15 The control unit 240 of the terminal 20 shown can also be implemented by a control program stored in the storage device 1002 and operated in the processor 1001. Regarding the various processes described above, the case executed by one processor 1001 has been explained, but it is also possible for two or more processors 1001 to execute them simultaneously or sequentially. The processor 1001 can also be implemented using one or more chips. Furthermore, the program can also be transmitted from a network via a telecommunications line.

[0331] Storage device 1002 is a computer-readable recording medium, and may be composed of at least one of ROM (Read-Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. Storage device 1002 may also be referred to as a register, cache, main memory (main storage device), etc. Storage device 1002 is capable of storing programs (program code), software modules, etc., that are executable for implementing the communication method according to an embodiment of this disclosure.

[0332] The auxiliary storage device 1003 is a computer-readable recording medium, and may be composed of at least one of the following: CD-ROM (Compact Disc ROM) or other optical discs, hard disks, flexible disks, optical discs (e.g., compact discs, digital multifunction discs, Blu-ray discs), smart cards, flash memory (e.g., cards, sticks, key drives), floppy disks, magnetic stripes, etc. The aforementioned storage medium may also be other suitable media such as databases or servers that include at least one of the storage device 1002 and the auxiliary storage device 1003.

[0333] The communication device 1004 is hardware (transmitting and receiving device) used for communication between computers via at least one of a wired network and a wireless network. It is also referred to as a network device, network controller, network interface card (NIC), communication module, etc. To implement at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD), the communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. For example, transmitting and receiving antennas, amplifier units, transmitting and receiving units, transmission path interfaces, etc., can also be implemented by the communication device 1004. The transmitting and receiving units can also be implemented by physically or logically separating the transmitting unit and the receiving unit.

[0334] Input device 1005 is an input device that accepts input from external sources (e.g., keyboard, mouse, microphone, switch, button, sensor, etc.). Output device 1006 is an output device that performs output to external sources (e.g., display, speaker, LED light, etc.). Alternatively, input device 1005 and output device 1006 can also be an integrated structure (e.g., touch panel).

[0335] Furthermore, the processor 1001 and storage device 1002, among other devices, are connected via a bus 1007 for communicating information. The bus 1007 can be configured as a single bus or as different buses between the devices.

[0336] Furthermore, the base station 10 and the terminal 20 can also be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and can also use this hardware to implement part or all of the functional blocks. For example, the processor 1001 can also be implemented using at least one of these hardware components.

[0337] exist Figure 17 The diagram shows a structural example of vehicle 2001. For example... Figure 17 As shown, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a gear shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, an electronic control unit 2010, various sensors 2021-2029, an information service unit 2012, and a communication module 2013. The various methods / implementations described in this disclosure can also be applied to communication devices mounted on the vehicle 2001, for example, they can also be applied to the communication module 2013.

[0338] The drive unit 2002 is configured, for example, as an engine, a motor, or a combination of an engine and a motor. The steering unit 2003 is configured to include at least a steering wheel (also called a handlebar) and to steer at least one of the front and rear wheels based on the operation of the steering wheel by the user.

[0339] The electronic control unit 2010 consists of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals from various sensors 2021 to 2029 of the vehicle 2001 are input into the electronic control unit 2010. The electronic control unit 2010 can also be referred to as an ECU (Electronic Control Unit).

[0340] The signals from various sensors 2021 to 2029 include current signals from current sensor 2021 that senses the current of the motor, speed signals of the front and rear wheels obtained by speed sensor 2022, air pressure signals of the front and rear wheels obtained by air pressure sensor 2023, vehicle speed signals obtained by vehicle speed sensor 2024, acceleration signals obtained by acceleration sensor 2025, accelerator pedal depress amount signals obtained by accelerator pedal sensor 2029, brake pedal depress amount signals obtained by brake pedal sensor 2026, shift lever operation signals obtained by shift lever sensor 2027, and detection signals obtained by object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0341] The information service unit 2012 comprises various devices such as a car navigation system, audio system, speakers, loudspeakers, television, and radio, used to provide (output) various information such as driving information, traffic information, and entertainment information, as well as one or more ECUs that control these devices. The information service unit 2012 uses information obtained from external devices via a communication module 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001. The information service unit 2012 may include input devices that accept input from external sources (e.g., keyboard, mouse, microphone, switch, button, sensor, touch panel, etc.) and output devices that perform output to external sources (e.g., display, speaker, LED lights, touch panel, etc.).

[0342] The driver assistance system unit 2030 comprises various devices used to provide functions for preventing accidents or reducing the driver's workload, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning devices (e.g., GNSS), map information (e.g., high-resolution (HD) maps, autonomous vehicle (AV) maps), gyroscope systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System)), AI (Artificial Intelligence) chips, and AI processors, and one or more ECUs that control these devices. Furthermore, the driver assistance system unit 2030 sends and receives various information via the communication module 2013 to realize driver assistance or autonomous driving functions.

[0343] The communication module 2013 can communicate with the microprocessor 2031 and the constituent elements of the vehicle 2001 via a communication port. For example, the communication module 2013 sends and receives data with the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, gear shift lever 2006, front wheel 2007, rear wheel 2008, axle 2009, microprocessor 2031 in the electronic control unit 2010, memory (ROM, RAM) 2032, and sensors 2021 to 29 in the vehicle 2001 via the communication port 2033.

[0344] The communication module 2013 can be controlled by the microprocessor 2031 of the electronic control unit 2010 and is a communication device capable of communicating with external devices. For example, it can send and receive various types of information wirelessly with external devices. The communication module 2013 can be located either inside or outside the electronic control unit 2010. External devices can be, for example, base stations, mobile stations, etc.

[0345] The communication module 2013 can also wirelessly transmit to an external device at least one of the signals input to the electronic control unit 2010 from the various sensors 2021-2028, information obtained based on those signals, and information input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021-2028, and the information service unit 2012 can also be referred to as input units that receive input. For example, the PUSCH transmitted via the communication module 2013 can also contain information based on the aforementioned inputs.

[0346] The communication module 2013 receives various information (traffic information, signal information, vehicle-to-vehicle information, etc.) sent from external devices and displays it to the information service unit 2012 of the vehicle 2001. The information service unit 2012 can also be referred to as an output unit that outputs information (e.g., outputs information to devices such as displays and speakers based on the PDSCH received by the communication module 2013 (or data / information decoded from the PDSCH)). Furthermore, the communication module 2013 stores various information received from external devices into a memory 2032 that can be utilized by the microprocessor 2031. The microprocessor 2031 can also control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, gear shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021-2029, etc., of the vehicle 2001 based on the information stored in the memory 2032.

[0347] (Summary of implementation methods)

[0348] As described above, according to an embodiment of the present invention, a network node is provided, comprising: a receiving unit for receiving a message requesting LTM (Lower layer Triggered Mobility) from other network nodes; a control unit for determining which cell to set as an LTM candidate; and a sending unit for sending a UE context establishment request to a subordinate DU (Distributed Unit) based on the decision, wherein the receiving unit receives a UE context establishment response from the DU, and the sending unit sends a response to the message to the other network nodes.

[0349] The above structure allows for the setting of LTM between CUs and LTM in DCs, or conditional LTM, for the UE. That is, it can expand the application scope of LTM (Lower layer Triggered Mobility) to enhance mobility.

[0350] The control unit can also include information related to lower-level settings in the response. This structure enables the UE to set LTMs between CUs and in the DC, or conditional LTMs.

[0351] The control unit may also include the ID of the source base station or the target base station in the UE context establishment request. This structure enables the setting of inter-CU LTM and DC LTM, or conditional LTM, for the UE.

[0352] The control unit can also decide whether to execute the early random access channel for each target cell. This structure allows for the configuration of inter-CU LTM and DC LTM, or conditional LTM, for the UE.

[0353] The control unit can also determine the execution conditions for conditional LTM and include the execution conditions in the response or the UE context establishment request. This structure enables the setting of inter-CU LTM and DC LTM, or conditional LTM, for the UE.

[0354] Furthermore, according to embodiments of the present invention, a communication method is provided, performed by a network node: a process of receiving a message requesting LTM (Lower layer Triggered Mobility) from other network nodes; a process of determining which cell to set as an LTM candidate; a process of sending a UE context establishment request to a subordinate DU (Distributed Unit) based on the decision; a process of receiving a UE context establishment response from the DU; and a process of sending a response to the message to the other network nodes.

[0355] The above structure allows for the setting of LTM between CUs and LTM in DCs, or conditional LTM, for the UE. That is, it can expand the application scope of LTM (Lower layer Triggered Mobility) to enhance mobility.

[0356] (Supplement to the implementation method)

[0357] The embodiments of the present invention have been described above, but the disclosed invention is not limited to these embodiments. Those skilled in the art should understand various modifications, alterations, substitutions, and replacements. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these values ​​are merely examples, and any appropriate values ​​may be used. The distinctions between items in the above description are not essential to the present invention. Items described in two or more items may be combined as needed, and items described in one item may be applied to items described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical components. Physically, one component may perform the operation of multiple functional units, or multiple components may perform the operation of one functional unit. Regarding the processing described in the embodiments, the order of processing may be interchanged unless there is a contradiction. For ease of explanation, a functional block diagram has been used to describe the base station 10 and the terminal 20, but such a device may also be implemented in hardware, software, or a combination thereof. The software operating via the processor of the base station 10 according to an embodiment of the present invention and the software operating via the processor of the terminal 20 according to an embodiment of the present invention can also be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or other suitable storage media, respectively.

[0358] Furthermore, the notification of information is not limited to the methods / implementations described in this disclosure, and other methods may also be used. For example, the notification of information may also be implemented through physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. In addition, RRC signaling may also be referred to as an RRC message, for example, it may be an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc.

[0359] The various methods / implementations described in this disclosure can also be applied to LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal)), FRA (Future Radio Access), NR (New Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE The system may use at least one of the following: 802.16 (WiMAX, a registered trademark), IEEE 802.20, UWB (Ultra-Wideband), Bluetooth (Bluetooth, a registered trademark), systems using other suitable systems, and next-generation systems that are extended, modified, generated, or specified based on these. Furthermore, multiple systems may be combined (e.g., a combination of at least one of LTE and LTE-A with 5G).

[0360] The processing procedures, timing, flowcharts, etc., of the various methods / implementations described in this specification may be rearranged in order, provided there is no contradiction. For example, for the methods described in this disclosure, the elements of various steps are indicated using an illustrative order, but are not limited to the specific order indicated.

[0361] In this specification, certain operations described as being performed by base station 10 may sometimes be performed through its upper node, depending on the circumstances. Clearly, in a network consisting of one or more network nodes including base station 10, various operations for communicating with terminal 20 can be performed by at least one of base station 10 and other network nodes besides base station 10 (e.g., MME or S-GW, but not limited to these). The above example illustrates a single network node other than base station 10, but other network nodes can also be a combination of multiple other network nodes (e.g., MME and S-GW).

[0362] Information or signals described in this disclosure may be output from a higher (or lower) layer to a lower (or higher) layer. They may also be input or output via multiple network nodes.

[0363] The input and output information can be stored in a specific location (e.g., memory) or managed using a management table. The input and output information can be overwritten, updated, or appended. Output information can also be deleted. Input information can also be sent to other devices.

[0364] The determination in this disclosure can be made by a value represented by 1 bit (0 or 1), by a true or false value (Boolean: true or false), or by a comparison of numerical values ​​(e.g., a comparison with a specific value).

[0365] Whether it is called software, firmware, middleware, microcode, hardware description language, or any other name, software should be broadly interpreted as instructions, instruction sets, code, code segments, program code, program, subprogram, software module, application, software application, software package, routine, subroutine, object, executable file, execution thread, process, function, etc.

[0366] Furthermore, software, instructions, and information can also be sent and received via a transmission medium. For example, when software is sent from a website, server, or other remote source using at least one of wired technologies (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technologies (infrared, microwave, etc.), at least one of these wired and wireless technologies is included within the definition of a transmission medium.

[0367] The information, signals, etc., described in this disclosure can also be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc., which may be mentioned throughout the above description, can also be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0368] Furthermore, the terms described in this disclosure and those necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and the symbol may also be a signal (signaling). Additionally, a signal may also be a message. Furthermore, a component carrier (CC) may also be referred to as a carrier frequency, cell, frequency carrier, etc.

[0369] The terms “system” and “network” used in this disclosure are interchangeable.

[0370] Furthermore, the information, parameters, etc., described in this disclosure can be represented by absolute values, relative values ​​with respect to a specific value, or other corresponding information. For example, wireless resources can also be indicated by a specific index.

[0371] The names used for the parameters described above are not limiting names in any respect. Furthermore, the mathematical formulas, etc., using these parameters sometimes differ from those explicitly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name; therefore, the various names assigned to these various channels and information elements are not limiting names in any respect.

[0372] In this disclosure, the terms "base station (BS)," "wireless base station," "base station device," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" are used interchangeably. There are also instances where terms such as macro cell, small cell, femtocell, and picocell are used to refer to base stations.

[0373] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, its overall coverage area can be divided into several smaller areas, each of which can also provide communication services through a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). Terms such as "cell" or "sector" refer to a portion or all of the coverage area of ​​the base station and at least one of the base station subsystems providing communication services within that coverage area.

[0374] In this disclosure, the information sent by the base station to the terminal and the control and operation instructions given by the base station to the terminal based on that information can be rewritten.

[0375] In this disclosure, the terms “Mobile Station (MS),” “user terminal,” “user equipment (UE),” and “terminal” are used interchangeably.

[0376] There are also instances where those skilled in the art use terms such as subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, hand set, user agent, mobile client, client, or several other appropriate terms to refer to a mobile station.

[0377] At least one of the base station and the mobile station can also be referred to as a transmitting device, a receiving device, a communication device, etc. Furthermore, at least one of the base station and the mobile station can also be a device mounted on a moving object, the moving object itself, etc. The moving object refers to a movable object whose speed of movement is arbitrary. This also includes situations where the moving object is stationary. Examples of moving objects include vehicles, transport vehicles, automobiles, autonomous two-wheelers, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, trailers, rickshaws, ships (boats and other watercraft), airplanes, rockets, artificial satellites, drones (registered trademark), multi-rotor aircraft, quadcopters, balloons, and objects mounted on them, and are not limited to these. In addition, the moving object can also be a moving object that moves autonomously based on operating commands. It can be a means of transportation (e.g., vehicles, airplanes, etc.), a moving object that moves unmanned (e.g., drones, autonomous vehicles, etc.), or a robot (humanized or unmanned). In addition, at least one of the base station and the mobile station also includes a device that is not necessarily mobile during the communication operation. For example, at least one of the base station and the mobile station can also be an IoT (Internet of Things) device such as a sensor.

[0378] Furthermore, the base station in this disclosure can also be rewritten as a user terminal. For example, various methods / implementations of this disclosure can be applied to a structure that replaces the communication between the base station and the user terminal with communication between multiple terminals 20 (e.g., also referred to as D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). In this case, it can also be configured such that the terminal 20 has the functions of the base station 10 described above. In addition, terms such as "uplink" and "downlink" can also be rewritten as terms corresponding to inter-terminal communication (e.g., "side"). For example, uplink channel, downlink channel, etc., can also be rewritten as side channel.

[0379] Similarly, the user terminal in this disclosure can also be rewritten as a base station. In this case, it can also be configured such that the base station has the functions of the user terminal described above.

[0380] The terms "determining" and "determining" as used in this disclosure encompass a wide variety of actions. For example, "determining" and "determining" can include judging, calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or other data structure), and ascertaining. Furthermore, "determining" and "determining" can include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, and accessing (e.g., accessing data in memory). Additionally, "determining" and "determining" can include resolving, selecting, choosing, establishing, and comparing. In other words, "determining" and "determining" can encompass situations where certain operations are considered "determining" and "determining." In addition, "judgment (decision)" can also be rewritten as "assuming", "expecting", "considering", etc.

[0381] The terms “connected,” “coupled,” or all variations thereof, refer to all direct or indirect connections or combinations between two or more elements, and can include cases where there is one or more intermediate elements between two mutually “connected” or “coupled” elements. The connection or combination between elements can be physical, logical, or a combination thereof. For example, “connected” can also be rewritten as “access.” In the context of this disclosure, it is possible to consider two elements being mutually “connected” or “coupled” using at least one of one or more wires, cables, or printed electrical connections, and, as several non-limiting and non-exclusive examples, using electromagnetic energy with wavelengths in the wireless frequency domain, microwave region, or light (both visible and invisible) region.

[0382] The reference signal can also be simply referred to as RS (Reference Signal), or it can be called a pilot depending on the standard applied.

[0383] As used in this disclosure, the word "based on" does not mean "based on only" unless otherwise specified. In other words, the word "based on" means both "based on only" and "based on at least".

[0384] Any reference to an element using the designations "first," "second," etc., as used in this disclosure does not comprehensively limit the quantity or order of these elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Therefore, references to the first and second elements do not imply that only two elements may be used, or that the first element must take precedence over the second element in some form.

[0385] Alternatively, the term "unit" in the structure of the above devices can be replaced with "section", "circuit", "equipment", etc.

[0386] When the terms "include," "including," and variations thereof are used in this disclosure, these terms, like the term "comprising," mean inclusive. Furthermore, the term "or" as used in this disclosure does not mean XOR.

[0387] In this disclosure, for example, in cases where articles are added through translation, such as a, an, and the in English, the disclosure may also include cases where the noun following these articles is in a plural form.

[0388] In this disclosure, the term "A is different from B" can also mean "A and B are different from each other". Additionally, this term can also mean "A and B are different from C respectively". Terms such as "separate" and "combined" can also be interpreted in the same way as "different".

[0389] The various methods / implementations described in this disclosure can be used individually, in combination, or switched during execution. Furthermore, notification of specific information (e.g., a "It is X" notification) is not limited to explicit notification; it can also be implicit (e.g., by not notifying the user of that specific information).

[0390] The present disclosure has been described in detail above, but it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered ways without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the present disclosure is intended for illustrative purposes only and is not intended to be restrictive in any way.

[0391] Label Explanation

[0392] 10 Base station, 110 Transmitting unit, 120 Receiving unit, 130 Setting unit, 140 Control unit, 20 Terminal, 210 Transmitting unit, 220 Receiving unit, 230 Setting unit, 240 Control unit, 30 Network node, 1001 Processor, 1002 Storage device, 1003 Auxiliary storage device, 1004 Communication device, 1005 Input device, 1006 Output device.

Claims

1. A network node having: The receiving unit receives LTM (Low-Layer Triggered Mobility) messages from other network nodes; The control unit decides which cell to designate as an LTM candidate; and Based on the decision, the sending unit sends a UE context establishment request to its subordinate DU (Distributed Unit). The receiving unit receives a UE context establishment response from the DU. The sending unit sends a response to the message to the other network nodes.

2. The network node as described in claim 1, wherein, The control unit includes the information related to the lower-level settings in the response.

3. The network node as described in claim 1, wherein, The control unit includes the ID of the source base station or the target base station in the UE context establishment request.

4. The network node as described in claim 1, wherein, The control unit determines whether to execute the early random access channel for each target cell.

5. The network node as described in claim 1, wherein, The control unit determines the execution conditions of the conditional LTM and includes the execution conditions in the response or the UE context establishment request.

6. A communication method in which a network node performs the following process: The process of receiving LTM (Low-Level Mobility Trigger) messages from other network nodes; The process of deciding which cell to designate as an LTM candidate; Based on the aforementioned decision, the process of sending a UE context establishment request to the subordinate DU (Distributed Unit) is as follows: The process of receiving a UE context from the DU to establish a response; as well as The process of sending a response to the message to the other network nodes.

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