Method and apparatus for operating method when terminal receives RRC reconfiguration message including configuration of secondary cell group in next-generation mobile communication system

A method performed by a master cell group (MCG) in a wireless communication system, the method comprising:

• transmitting, to a terminal, a first radio resource control (RRC) message including RRC reconfiguration information;
• in case that the first RRC message is received via a first signaling radio bearer (SRB) and the RRC reconfiguration information is received within a first field associated with a new radio (NR) SCG, receiving, from the terminal, a second RRC message associated with the NR SCG;
• and
• in case that the first RRC message is received via the first SRB and the RRC reconfiguration information is received within a second field associated with an evolved universal terrestrial radio access (EUTRA) SCG, receiving, from the terminal, a third RRC message associated with the EUTRA SCG,
• wherein the first field and the second field are included in the field for the SCG configuration in multi-radio dual connectivity (MR-DC),
• wherein whether the first RRC message is received via the first SRB is identified by the terminal, and
• wherein whether the first RRC message includes a field for a secondary cell group (SCG) configuration in MR-DC is identified by the terminal.

A method performed by a secondary cell group (SCG) in a wireless communication system, the method comprising:

• transmitting, to a terminal, a first radio resource control (RRC) message including RRC reconfiguration information;
• and
• receiving, from the terminal, a second RRC message in case that the first RRC message is transmitted via a second signaling radio bearer (SRB) to a lower layer,
• wherein whether the first RRC message is received via the second SRB is identified by the terminal.

A terminal comprising:

• a transceiver configured to be capable of transmitting or receiving at least one signal;
• and
• a controller configured to be connected to the transceiver, the controller is configured to:
• receive a first radio resource control (RRC) message including RRC reconfiguration information,
• identify whether the first RRC message is received via a first signaling radio bearer (SRB) or a second SRB,
• identify whether the first RRC message includes a field for a secondary cell group (SCG) configuration in multi-radio dual connectivity (MR-DC),
• in case that the field for the SCG configuration in MR-DC is included in the first RRC message, identify whether the RRC reconfiguration information is received within a first field associated with a new radio (NR) SCG or a second field associated with an evolved universal terrestrial radio access (EUTRA) SCG, wherein the first field and the second field are included in the field for the SCG configuration in MR-DC,
• in case that the first RRC message is received via the first SRB and the RRC reconfiguration information is received within the first field, perform an RRC reconfiguration on the NR SCG,
• in case that the first RRC message is received via the first SRB and the RRC reconfiguration information is received within the second field, perform an RRC reconfiguration on the EUTRA SCG, and
• in case that the first RRC message is received via the second SRB, perform an RRC reconfiguration on the NR SCG and transmitting a second RRC message via the second SRB to a lower layer.

A master cell group (MCG) comprising:

• a transceiver configured to be capable of transmitting or receiving at least one signal;
• and
• a controller configured to be connected to the transceiver,
• the controller is configured to:
• transmit, to a terminal, a first radio resource control (RRC) message including RRC reconfiguration information,
• in case that the first RRC message is received via a first signaling radio bearer (SRB) and the RRC reconfiguration information is received within a first field associated with a new radio (NR) SCG, and
• in case that the first RRC message is received via the first SRB and the RRC reconfiguration information is received within a second field associated with an evolved universal terrestrial radio access (EUTRA) SCG, receiving, from the terminal, a third RRC message associated with the EUTRA SCG,
• wherein the first field and the second field are included in the field for the SCG configuration in multi-radio dual connectivity (MR-DC),
• wherein whether the first RRC message is received via the first SRB is identified by the terminal, and
• wherein whether the first RRC message includes a field for a secondary cell group (SCG) configuration in MR-DC is identified by the terminal.

A secondary cell group (SCG) comprising:

• a transceiver configured to be capable of transmitting or receiving at least one signal;
• and
• a controller configured to be connected to the transceiver,
• wherein the controller is configured to:
• transmit, to a terminal, a first radio resource control (RRC) message including RRC reconfiguration information, and
• receive, from the terminal, a second RRC message in case that the first RRC message is transmitted via a second signaling radio bearer (SRB) to a lower layer,
• wherein whether the first RRC message is received via the second SRB is identified by the terminal.