Disclosed in some examples is a method performed by a relay station, the method including receiving at a relay station a data packet transmitted from a base station to a subscriber station; receiving a non-acknowledgement (NACK) message transmitted from the subscriber station to the base station in response to the data packet; receiving resource allocation information transmitted from the base station to the subscriber station; and transmitting, in response to the received NACK message at the transmission time, the data packet to the subscriber station in a resource allocation allocated for a retransmission of the data packet from the base station to the subscriber station, wherein the resource allocation is determined from the resource allocation information.