Patent ID: 7760687

Claim:
A method of data retransmission in a multi carrier system, (a) receiving, by an user equipment, a first grant message including a first New Data Indicator (NDI) and a first resource allocation information for an uplink data transmission, wherein the first NDI indicates whether a new data is transmitted or retransmitted; (b) transmitting the uplink data according to the first resource allocation information; and (c) receiving an acknowledgement message representing whether the uplink data is successfully received; (d-0) when a second grant message including second resource allocation information for the uplink data retransmission and a second NDI which is not toggled compare with the first NDI at the step of (c), the method further comprising: adaptively retransmitting the uplink data using the second resource allocation information; (d-1) when the second grant message is not received and the acknowledgement message is a negative acknowledgement (NACK) message, the method further comprising: non-adaptively retransmitting the uplink data using the first resource allocation information.