| CPC H04W 76/27 (2018.02) [H04B 7/06964 (2023.05); H04W 72/27 (2023.01)] | 13 Claims |

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1. A user apparatus in a communication system, the user apparatus comprising:
a processor coupled to a memory storing instructions for the processor,
the communication system comprising the user apparatus and a plurality of base stations configured to wirelessly communicate with the user apparatus, wherein
the user apparatus operates in one of a radio resource control RRC_CONNECTED state, an RRC_INACTIVE state, and an RRC_IDLE state transitionable to each other,
the plurality of base stations include a plurality of master nodes including a first master node and a second master node and one or more secondary nodes, the plurality of master nodes each having a cell group including a primary cell and one or more secondary cells, the one or more secondary nodes each having a cell group including a primary cell and one or more secondary cells,
each master node and each secondary node support dual connectivity for the user apparatus,
the user apparatus performs a procedure for switching a destination of the user apparatus for the dual connectivity from the first master node, which is a source master node, to the second master node, which is a target master node, and resuming the user apparatus from the RRC_INACTIVE state to the RRC_CONNECTED state,
wherein, in the procedure, the user apparatus transmits, to the second master node, a resume request message including a identifier allocated by the first master node in transitioning from the RRC_CONNECTED state to the RRC_INACTIVE state, and
in the procedure, the user apparatus receives, from the second master node, a resume message related to resuming to the RRC_CONNECTED state, and executes release of a configuration related to a secondary node of the each secondary node based on the resume message.
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