Aspects provide a mechanism for activating a secondary serving cell (SCell) in a wireless communication network supporting a multi-cell transmission environment. In some examples, a scheduled entity (e.g., a UE) in a connected mode with a primary serving cell (PCell) may synchronize with the SCell to activate the SCell for multi-cell communication with the PCell and the SCell. To enable synchronization with the SCell, the PCell may trigger communication and processing of one or more reference signals between the scheduled entity and the SCell.