Patent ID: 8310988

Claim:
A method of receiving data at a receiving side of a mobile communication system, the method comprising: receiving data from a transmitting side, the data including a first media access control (MAC) header that is uncompressed; transmitting a message to the transmitting side, the message including an ACK signal if there is no error in the first MAC header or including a NACK signal if there is an error in the first MAC header; and receiving data from the transmitting side, the data including a second MAC header generated in accordance with the message, wherein the second MAC header is generated by compression if the message includes the ACK signal or is generated without compression if the message includes the NACK signal, wherein the second MAC header that is generated by compression includes at least a flag field indicating whether the second MAC header has been compressed, a connection index (CIND) for identifying a service flow (SF), an error detection field for detecting whether the header has an error, or a field representing a size of a MAC message, and wherein the CIND is uniquely used to identify the SF within the receiving side.