A Buffer Status Report (BSR) is of great importance in an uplink system due to its provision of User Equipment (UE) side information required for scheduling at a base station (evolved NodeB or eNB). In the Long Term Evolution-Advance (LTE-A) Release 8/9, a buffer status report is relatively simple because there is only one Media Access Control Protocol Data Unit (MAC PDU) in each Transport Time Interval (TTI). However in the LTE-A Release 10, a plurality of MAC PDUs can be transmitted in one TTI due to the introduction of Carrier Aggregation (CA), i.e., a plurality of Component Carriers (CCs), and thus it is desirable to address some new issues occurring with a buffer status report.