Method and system for UE actions upon SCG activation and deactivation

A user equipment (UE) in a wireless communication system, the UE comprising:

• a transceiver;
• and
• at least one processor coupled with the transceiver and configured to:
• receive, from a network, a radio resource control (RRC) reconfiguration message including configuration information indicating a deactivation of a secondary cell group (SCG) of the UE and a field for a beam failure detection (BFD) and a radio link monitoring (RLM) associated with the SCG of the UE,
• perform a medium access control (MAC) reset based on the configuration information,
• in case that the field is set to perform the BFD and the RLM, perform the BFD and the RLM on a primary SCG cell (PSCell) of the SCG of the UE when the SCG of the UE is deactivated, and
• in case that the field is set to not perform the BFD and the RLM, stop a timer T310 and a timer T312 when the SCG of the UE is deactivated.