Patent ID: 8611374

Claim:
A reordering method for a terminal to reorder protocol data units (PDUs), the terminal supporting a hybrid automatic retransmission request (HARQ) and including a Convergence Sublayer (CS) and reassembling function unit that assembles reordered PDUs to a service data unit (SDU), the reordering method comprising: storing a received PDU of which a sequence number is greater than the first sequence number of a PDU reordering sequence in a reordering buffer that stores PDUs queued for reordering; determining whether to drop a PDU of the first sequence number based on an average size of a buffer that is required for storing the received PDU; updating the first sequence number with the next sequence number of a dropped PDU; transmitting a PDU of which a sequence number is the same as the updated first sequence number among the PDUs queued in the reordering buffer to the CS and reassembling function unit; and updating the first sequence number with the next sequence number of the PDU transmitted to the CS and reassembling function unit.