Abstract: A method is provided for transmitting and receiving data in a multi-hop wireless mobile communication system having a first mobile station (MS), a second MS, a base transceiver station (BTS), and a relay BTS. The method includes allowing the first MS to directly communicate with the BTS, and allowing the second MS to communicate with the BTS by relay of the relay BTS; performing communication between the BTS and the first MS and communication between the relay BTS and the second MS using a first frame; and performing communication between the BTS and the relay BTS using a second frame.

Abstract: A method is provided for transmitting a packet data unit (PDU) by a transmitter in a wireless mobile communication system. The method includes determining at least one desired transmission PDU, determining a modulation scheme corresponding to the number of PDUs, and transmitting a first indicator value indicating the number of PDUs and the modulation scheme, transmitting the PDUs, receiving a second indicator value indicating a reception state of the PDUs, from a receiver that receives the PDUs, determining a new PDU or a retransmission PDU according to the second indicator value, and determining a modulation scheme corresponding to the number of the determined PDUs, and transmitting a third indicator value indicating the number of PDUs and the modulation scheme, and the corresponding PDUs.