According to certain embodiments, a method for activating and deactivating multiple secondary cells (150A-B) includes receiving a first message requesting activation or deactivation of a first secondary cell (first SCell) (150A) for a first carrier. In response to the first message, a first procedure is initiated to activate or deactivate the first SCell (150A). The wireless device (110A) may have a first delay period (Tactivate_basic) within which to complete the first procedure. While performing the first procedure to activate or deactivate the first SCell (150A), a second message to activate, deactivate, configure or deconfigure a second SCell (150B) for a second carrier is received. In response to receiving the second message to activate, deactivate, configure, or deconfigure the second SCell (150B), the first procedure may be modified by replacing the first delay period with a second delay period (Tactivate_total) within which to complete the first procedure to activate or deactivate the first SCell (150A). The second delay period (Tactivate_total) may be greater than the first delay period (Tactivate basic).