Patent ID: 8891428

Claim:
A method for transmitting data for a plurality of mobile stations (AMS) to a relay station (ARS) by a base station (ABS) in a wireless access system, the method comprising: generating an Extended Header (EH) including a plurality of STIDs (Station Identifiers) for the plurality of mobile stations; and transmitting a MAC PDU (medium access control protocol data unit) including the EH to the relay station, wherein a first STID for a first mobile station in the EH includes a first 1 bit field indicating whether a presence or non-presence of a next transmitted EH and a second 1 bit field indicating whether a second STID of a second mobile station different from the first mobile station is accompanied behind the first STID in the EH, wherein the second STID for the second mobile station is added into the EH without the first 1 bit field only if the second 1 bit field for the first STID is set to ‘0’.