Patent ID: 8306061

Claim:
A method of retransmitting a data unit in wireless communication system, the method comprising: transmitting the data unit to a peer receiving ARQ (Automatic Repeat Request) entity; receiving a delivery failure indication for the data unit from a transmitting HARQ (Hybrid Automatic Repeat Request) entity; wherein the delivery failure indication is a HARQ delivery failure notification; determining whether a delivery status indication for the data unit was previously received from the peer receiving ARQ entity, wherein the delivery status indication is a status PDU (Protocol Data Unit); and selectively retransmitting the data unit based on the determining step, wherein if the delivery status indication from the peer receiving ARQ entity indicates a successful delivery, the delivery failure indication from the transmitting HARQ entity is ignored such that the unnecessary retransmission of the data unit can be prevented due to an ACK-to-NACK error, and wherein the data unit is retransmitted to the peer receiving ARQ entity, if the delivery status indication from the peer receiving ARQ entity indicates an unsuccessful delivery or if the delivery status indication from the peer receiving ARQ entity does not exist.