Communication apparatus, base station, and communication method

A base station, comprising:

• a transmitter configured to:
• transmit, to a communication apparatus, a radio resource control (RRC) message including Layer 1/Layer 2 triggered mobility (LTM) configuration information, the LTM configuration information including information associated with a serving cell and one or more LTM candidate information configurations to be added or modified, the information associated with the serving cell being used for determining whether or not to perform a security key update procedure, and
• transmit, to the communication apparatus, a cell switch command medium access control (MAC) control element (CE) that triggers an LTM cell switch procedure;
• and
• a controller configured to control the communication apparatus to perform the LTM cell switch procedure based on the cell switch command MAC CE, wherein
• the controller is configured to control, based on the information associated with the serving cell included in the LTM configuration information, whether or not to perform the security key update procedure in a case where the LTM cell switch procedure is performed.

A communication method of a communication apparatus, comprising the steps of:

• receiving, from a base station, a radio resource control (RRC) message including Layer 1/Layer 2 triggered mobility (LTM) configuration information, the LTM configuration information including information associated with a serving cell and one or more LTM candidate information configurations to be added or modified, the information associated with the serving cell being used for determining whether or not to perform a security key update procedure;
• receiving, from the base station, a cell switch command medium access control (MAC) control element (CE) that triggers an LTM cell switch procedure;
• performing the LTM cell switch procedure based on the cell switch command MAC CE;
• and
• determining, based on the information associated with the serving cell included in the LTM configuration information, whether or not to perform the security key update procedure in a case where the LTM cell switch procedure is performed.