Efficient relay automatic repeat request procedure in broadband wireless access system

A data relay method through which a relay station relays data regarding at least one mobile station (AMS) in a broadband wireless access system including the relay station, comprising:

• receiving at least one first unit data from a first station;
• generating at least one third unit data using second unit data respectively included in the at least one first unit data;
• and
• transmitting the at least one third unit data to a second station,
• wherein the second unit data includes a plurality of fourth unit data to which different relay sequence numbers are respectively assigned.

A relay station (ARS) system which relays data exchanged between a base station (ABS) and at least one mobile station (AMS) in a broadband wireless access system, comprising:

• a processor;
• and
• a wireless communication (RF) module to transmit and receive a wireless signal with the outside under control of the processor, wherein
• the processor generates at least one third unit data using second unit data respectively included in at least one first unit data received from a first station, and transmits the at least one third unit data to a second station;
• and
• the second unit data includes a plurality of fourth unit data to which different relay sequence numbers are respectively assigned.