US-20260129544-A1 - BASE STATION APPARATUS FOR EFFICIENT CONNECTION PROCESSING, TERMINAL APPARATUS, AND CONTROL METHOD

US20260129544A1US 20260129544 A1US20260129544 A1US 20260129544A1US-20260129544-A1

Abstract

A base station apparatus obtains information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPAC) in a terminal apparatus that is currently connected to the base station apparatus, the information including a reference configuration and a delta configuration that corresponds to a difference between the setting information and the reference configuration, and provides the terminal apparatus with the information and a condition under which the CPAC is to be executed.

Inventors

Yanwei LI
Hiroki Takeda
Yoshitaka TAKAKU
Jungyeon HONG

Assignees

KDDI CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251104
Priority Date: 20230512

Claims (16)

1 . A base station apparatus, comprising: an obtaining unit configured to obtain information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPAC) in a terminal apparatus that is currently connected to the base station apparatus, the information including a reference configuration and a delta configuration that corresponds to a difference between the setting information and the reference configuration; and a providing unit configured to provide the terminal apparatus with the information and a condition under which the CPAC is to be executed.
2 . The base station apparatus according to claim 1 , wherein the obtaining unit obtains the delta configuration of the candidate cell by generating a first reference configuration, notifying another base station apparatus that forms the candidate cell of the first reference configuration, transmitting an instruction for generating the delta configuration of the candidate cell to the other base station, and receiving a response to the instruction.
3 . The base station apparatus according to claim 2 , wherein the other base station apparatus generates a second reference configuration upon receiving the first reference configuration, the obtaining unit further obtains the second reference configuration from the other base station apparatus, and the delta configuration of the candidate cell corresponds to a difference between the setting information and the second reference configuration.
4 . The base station apparatus according to claim 1 , wherein the obtaining unit obtains the reference configuration and the delta configuration related to the candidate cell by requesting another base station apparatus that provides the candidate cell to generate the reference configuration and the delta configuration, and receiving a response to the request.
5 . A terminal apparatus, comprising: an obtaining unit configured to obtain, from a base station apparatus to which the terminal apparatus is currently connected, information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPAC), and a condition under which the CPAC is to be executed, the information including a reference configuration and a delta configuration that corresponds to a difference between the setting information and the reference configuration; a generating unit configured to generate, with respect to the candidate cell, setting information for communication in the candidate cell with use of the delta configuration and the reference configuration, and an executing unit configured to execute the CPAC with use of the generated setting information in response to the condition being satisfied.
6 . The terminal apparatus according to claim 5 , wherein the reference configuration is generated by the base station apparatus, or by another base station apparatus that provides a candidate cell targeted for the CPAC.
7 . The terminal apparatus according to claim 5 , further comprising a receiving unit configured to receive, from the base station apparatus, information indicating whether the reference configuration is usable in generation of the setting information.
8 . The terminal apparatus according to claim 5 , wherein when the reference configuration and the delta configuration that is to be combined with the reference configuration are received, the generating unit generates setting information for communication in a cell corresponding to the delta configuration with use of the reference configuration and the delta configuration.
9 . The terminal apparatus according to claim 5 , wherein after the reference configuration and the delta configuration that is to be combined with the reference configuration are received, in response to a measured wireless quality satisfying a predetermined condition, the generating unit generates setting information for communication in a cell corresponding to the delta configuration with use of the reference configuration and the delta configuration.
10 . The terminal apparatus according to claim 5 , further comprising a determining unit configured to, after the reference configuration and the delta configuration are received and the setting information for communication in a cell corresponding to the delta configuration is generated by the generating unit with use of the reference configuration and the delta configuration, determine an appropriateness of the setting information.
11 . The terminal apparatus according to claim 10 , wherein the determining unit determines the appropriateness in response to a measured wireless quality satisfying a predetermined condition.
12 . The terminal apparatus according to claim 10 , wherein when the reference configuration and the delta configuration are received, the determining unit determines the appropriateness of each of the reference configuration and the delta configuration.
13 . The terminal apparatus according to claim 10 , further comprising a notifying unit configured to, in a case where the determining unit determines that the setting information is inappropriate, transmit a notification including information indicating that an error occurred to the base station apparatus to which the terminal apparatus is currently connected.
14 . The terminal apparatus according to claim 13 , wherein the notification includes scg-reconfigFailure as the information indicating that the error occurred.
15 . A control method executed by a base station apparatus, the control method comprising: obtaining information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPAC) in a terminal apparatus that is currently connected to the base station apparatus, the information including a reference configuration and a delta configuration that corresponds to a difference between the setting information and the reference configuration; and providing the terminal apparatus with the information and a condition under which the CPAC is to be executed.
16 . A control method executed by a terminal apparatus, the control method comprising: obtaining, from a base station apparatus to which the terminal apparatus is currently connected, information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPAC), and a condition under which the CPAC is to be executed, the information including a reference configuration and a delta configuration that corresponds to a difference between the setting information and the reference configuration; generating, with respect to the candidate cell, setting information for communication in the candidate cell with use of the delta configuration and the reference configuration, and executing the CPAC with use of the generated setting information in response to the condition being satisfied.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a continuation of International Patent Application No. PCT/JP2024/016873 filed on May 2, 2024, which claims priority to and the benefit of Japanese Patent Application No. No. 2023-079344 filed on May 12, 2023, the entire disclosures of which are incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a technique to improve efficiency in wireless connection processing. Description of the Related Art In order to ensure the continuity of communication, a cellular communication system uses a handover technique to switch a connection destination of a terminal apparatus in accordance with, for example, movement of the terminal apparatus. In a standard method of handover, after degradation of the communication quality of a wireless link to which a terminal apparatus is currently connected, setting processing for a handover is started on the core network side, and a base station apparatus transmits an instruction message to the terminal apparatus. However, with this method, the processing performed from when the actual degradation of the communication quality occurs until the transmission of a handover instruction is time-consuming, and this can possibly prolong the time period for which communication cannot be performed or for which the communication quality is insufficient. In this regard, the 3rd Generation Partnership Project (3GPP®) has discussed a method in which this setting processing is executed in advance, and in a case where a predetermined condition is satisfied in the terminal apparatus, the connection destination cell is switched without needing to receive an instruction message from the base station apparatus (see NPL 1). The predetermined condition includes, for example, a case where the wireless quality of a neighboring cell has become more favorable than the wireless quality of the cell to which the terminal apparatus is currently connected by a predetermined level or more, and a case where the wireless quality of the cell to which the terminal apparatus is currently connected has become a predetermined value or lower. According to this method, setting processing for a handover is completed on the core network side before the occurrence of, for example, a decrease in the communication quality that requires a handover, and therefore it is possible to significantly reduce the time period for which communication cannot be performed or for which the communication quality is insufficient. Such a handover is referred to as a conditional handover, or a CHO. Similarly, for example, in multi-connectivity (MC) where a terminal apparatus connects to a plurality of cells, setting processing can be executed in advance, and in a case where a predetermined condition is satisfied in the terminal apparatus, the terminal apparatus can add or change a secondary cell without receiving an instruction message from a base station apparatus. Note that hereinafter, this conditional addition or change of a secondary cell may be referred to as CPAC. CITATION LIST Non-Patent Literature NPL 1:3GPP TR38.874, V16.0.0, December 2018 In a discussion on the release 18 standard of the 3GPP, it was agreed that in the aforementioned setting processing, setting processing is to be executed using a common reference configuration for a plurality of candidate cells, and delta configurations that designate setting values different from that of the reference configuration for the respective candidate cells. However, an execution procedure of such setting processing has been unclear, and there is demand for establishment of an efficient procedure. SUMMARY OF THE INVENTION The present invention provides a method of efficiently executing setting processing that uses a reference configuration and a delta configuration related to a conditional handover or a conditional secondary cell addition or change, in a terminal apparatus. A base station apparatus according to one aspect of the present invention comprises an obtaining unit configured to obtain information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPAC) in a terminal apparatus that is currently connected to the base station apparatus, the information including a reference configuration and a delta configuration that corresponds to a difference between the setting information and the reference configuration; and a providing unit configured to provide the terminal apparatus with the information and a condition under which the CPAC is to be executed. A terminal apparatus according to one aspect of the present invention comprises an obtaining unit configured to obtain, from a base station apparatus to which the terminal apparatus is currently connected, information for generating setting information related to a candidate cell targeted for a conditional secondary cell addition or change (CPA