Patent ID: 8325669

Claim:
A user equipment (UE) for uplink data retransmission in a multi carrier system, the UE comprising: a transmission module controlling an uplink data transmission and the uplink data retransmission; a receiving module controlling receiving of a message and a signal used in the uplink data retransmission; and a processor controlling the transmission module and the receiving module to perform the uplink data retransmission, wherein the processor is configured to: receive a first grant message including a first New Data Indicator (NDI) and first resource allocation information for the uplink data transmission, wherein the first NDI indicates whether new data is transmitted or retransmitted; transmit uplink data according to the first resource allocation information; receive an acknowledgement message indicating whether the uplink data is successfully received; adaptively retransmit 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 with the acknowledgement message; and non-adaptively retransmit the uplink data using the first resource allocation information when the second grant message is not received and the acknowledgement message is a negative acknowledgement (NACK) message.