HI,
MAC CE will have bits representing the activation and deactivation of carrier components,So based on the condition whether to activate which carrier specific bit field in the MAC-CE will be set and for deactivation bit will be reseted.
So if we refer 36.321 6.1.3.8 as shown in field structure among 8 bits the first bit is reserved which indicates the primary carrier component and rest 7 bits indicates the all other secondary carrier components.
And mapping of these component carriers to these bits will be informed to the UE in SCellToAddMod-r10 in RRCConnectionreconfiguration.
