Methods inform an eNodeB on the transmit power status of a user equipment in a mobile communication system using component carrier (CC) aggregation. Also described is an implementation of these methods by hardware and in software. The invention proposes procedures that allow the eNodeB to recognize the power usage status of a UE in a communication system using carrier aggregation. The UE indicates to the eNodeB when the UE is close to using its total maximum UE transmit power or when it has exceeded the same. This is achieved by the UE including indicator(s) and/or new MAC CEs to one or more protocol data units transmitted on respective component carriers within a single sub-frame that is providing the eNodeB with power status information. The MAC CEs may report a per-UE power headroom. Alternatively, the MAC CEs may report per-CC power headrooms and/or power reductions applied to the respective uplink CCs.