Terminal apparatus, base station apparatus, and method

1. A terminal apparatus that communicates with a base station apparatus, the terminal apparatus comprising:

a receiver configured to receive, from the base station apparatus, a message related to Radio Resource Control (RRC) connection reconfiguration; and

a processor, wherein

the processor, based on a fact that a first configuration is included in the message related to the RRC connection reconfiguration,

generates a Medium Access Control (MAC) entity of a cell group including a target primary cell,

determines, based on the first configuration included in the message related to the RRC connection reconfiguration, a Data Radio Bearer (DRB) to which the first configuration is to be applied and a DRB to which the first configuration is not to be applied,

changes a primary cell with which a first Radio Link Control (RLC) entity and a first Dedicated Traffic CHannel (DTCH) logical channel of the DRB to which the first configuration is not to be applied are associated from a source primary cell to the target primary cell, and

establishes, for the DRB to which the first configuration is to be applied, a second RLC entity and a second DTCH logical channel for the target primary cell, wherein

the first configuration is a configuration for a handover in which transmission and/or reception of first user data is performed in a target cell in a state where transmission and/or reception of second user data is continued in a source cell.

2. A base station apparatus that communicates with a terminal apparatus, the base station apparatus comprising:

a processor configured to include a first configuration in a message related to Radio Resource Control (RRC) connection reconfiguration; and

a transmitter configured to transmit, to the terminal apparatus, the message related to the RRC connection reconfiguration, wherein

in a case that the first configuration is included in the message related to the RRC connection reconfiguration,

a Data Radio Bearer (DRB) to which the first configuration is to be applied and a DRB to which the first configuration is not to be applied are determined based on the first configuration,

a Medium Access Control (MAC) entity #e of a cell group including a target primary cell is generated,

a primary cell with which a first Radio Link Control (RLC) entity and a first Dedicated Traffic CHannel (DTCH) logical channel of the DRB to which the first configuration is not to be applied are associated is changed from a source primary cell to the target primary cell,

a second RLC entity and a second DTCH logical channel for the target primary cell for the DRB to which the first configuration is to be applied are established, and

the first configuration is a configuration for a handover in which transmission and/or reception of first user data is performed in a target cell in a state where transmission and/or reception of second user data is continued in a source cell.

3. A method for a terminal apparatus that communicates with a base station apparatus, the method comprising:

receiving, from the base station apparatus, a message related to Radio Resource Control (RRC) connection reconfiguration;

based on a fact that a first configuration is included in the message related to the RRC connection reconfiguration,

generating a Medium Access Control (MAC) entity of a cell group including a target primary cell;

determining, based on the first configuration included in the message related to the RRC connection reconfiguration, a Data Radio Bearer (DRB) to which the first configuration is to be applied and a DRB to which the first configuration is not to be applied;

changing a primary cell with which a first Radio Link Control (RLC) entity and a first Dedicated Traffic CHannel (DTCH) logical channel of the DRB to which the first configuration is not to be applied are associated from a source primary cell to the target primary cell; and

establishing, for the DRB to which the first configuration is to be applied, a second RLC entity and a second DTCH logical channel for the target primary cell, wherein

the first configuration is a configuration for a handover in which transmission and/or reception of first user data is performed in a target cell in a state where transmission and/or reception of second user data is continued in a source cell.

4. A method for a base station apparatus that communicates with a terminal apparatus, the method comprising:

including a first configuration in a message related to Radio Resource Control (RRC) connection reconfiguration; and

transmitting, to the terminal apparatus, the message related to the RRC connection reconfiguration, wherein

in a case that the first configuration is included in the message related to the RRC connection reconfiguration,

a Data Radio Bearer (DRB) to which the first configuration is to be applied and a DRB to which the first configuration is not to be applied are determined based on the first configuration,

a Medium Access Control (MAC) entity of a cell group including a target primary cell is generated,

a primary cell with which a first Radio Link Control (RLC) entity and a first Dedicated Traffic CHannel (DTCH) logical channel of the DRB to which the first configuration is not to be applied are associated is changed from a source primary cell to the target primary cell,

a second RLC entity and a second DTCH logical channel for the target primary cell for the DRB to which the first configuration is to be applied are established, and

the first configuration is a configuration for a handover in which transmission and/or reception of first user data is performed in a target cell in a state where transmission and/or reception of second user data is continued in a source cell.