Uplink timing synchronization maintenance in secondary cell group

Aspects are presented herein of apparatuses, systems, and methods for secondary cell group (SCG) addition. A wireless device may establish communication with a first base station that is comprised in a master cell group (MCG) and a second base station that is comprised in the SCG. The wireless device may maintain timing advance (TA) parameters for performing uplink communication with the second base station. The wireless device may perform a plurality of signal quality measurements after receiving an indication to deactivate the SCG. The wireless device may determine whether to reuse the TA parameters for communicating with the second base station after receiving an indication. The determination may be based on comparing one or more signal quality measurements of the second base station to one or more signal quality thresholds.