Patent ID: 7873007

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