Patent ID: 8428086

Claim:
A method for retransmitting a protocol data unit (PDU) in a mobile communication system, the method comprising: segmenting a first PDU to form one or more second PDUs if it is determined that the first PDU does not fit within a size indicated by a lower layer, wherein each of the one or more second PDUs fits within the size indicated by the lower layer, and wherein the first PDU comprises a header field and a data field; and transmitting the one or more second PDUs to the receiving side, wherein the segmenting the first PDU to form the one or more second PDUs comprises mapping only the data field, not the header field, of the first PDU to a data field of the one or more second PDUs and setting a header of each of the one or more second PDUs, and wherein the header of each of the one or more second PDUs includes a field indicating that the corresponding second PDU is segmented.