Method and apparatus for controlling retransmission on uplink in a wireless communication system supporting MIMO

A user equipment (UE) for controlling retransmission in a communication system, the UE comprising:

• a transceiver for transmitting and receiving data with a Node B;
• and
• a controller for controlling operations of receiving a negative acknowledgement (NACK) for at least one transport block among a plurality of transport blocks transmitted by the UE, from the Node B, determining a precoding matrix and a number of layers for retransmission, and retransmitting the at least one transport block using the determined precoding matrix and the determined number of layers,
• wherein the precoding matrix is predefined and the number of layers is equal to a number of layers corresponding to the at least one transport block, if the UE does not receive a physical downlink control channel (PDCCH) intended for the UE and a number of the at least one transport block is not equal to a number of the plurality of transport blocks.

A method for controlling retransmission by a Node B in a communication system, the method comprising:

• receiving a plurality of transport blocks transmitted by a user equipment (UE);
• transmitting a negative acknowledgement (NACK) for at least one transport block to the UE;
• determining a precoding matrix and a number of layers that the UE uses during retransmission of the at least one transport block in response to the NACK;
• and
• receiving the at least one transport block using the determined precoding matrix and the determined number of layers,
• wherein the precoding matrix is predefined and the number of layers is equal to a number of layers corresponding to the at least one transport block, if the UE does not receive a physical downlink control channel (PDCCH) intended for the UE and a number of the at least one transport block is not equal to a number of the plurality of transport blocks.

A Node B for controlling retransmission in a communication system, the Node B comprising:

• a transceiver for transmitting and receiving data with a user equipment (UE);
• and
• a controller for controlling operations of receiving a plurality of transport blocks transmitted by the UE, transmitting a negative acknowledgement (NACK) for at least one transport block to the UE, determining a precoding matrix and a number of layers that the UE uses during retransmission of the at least one transport block in response to the NACK, and receiving the at least one transport block using the determined precoding matrix and the determined number of layers,
• wherein the precoding matrix is predefined and the number of layers is equal to a number of layers corresponding to the at least one transport block, if the UE does not receive a physical downlink control channel (PDCCH) intended for the UE and a number of the at least one transport block is not equal to a number of the plurality of transport blocks.