Method and apparatus for transmitting downlink signal in a mimo wireless communication system

A method for transmitting a downlink signal by a base station to a user equipment, the method comprising:

• transmitting downlink control information (DCI) through a downlink control channel,
• wherein the DCI includes resource assignment information for downlink data, and
• wherein the DCI includes a new data indicator (NDI) for each of a first transport block and a second transport block;
• and
• transmitting the downlink data through a downlink data channel in accordance with the resource assignment information, the downlink data including at least the first transport block or the second transport block,
• wherein, if the first transport block or the second transport block is disabled, one layer among a first layer and a second layer is used for transmission of an enabled transport block,
• wherein 1-bit NDI of the disabled transport block included in the DCI indicates the one layer used for the transmission of the enabled transport block.

A user equipment for receiving a downlink signal from a base station, the user equipment comprising:

• a receiving module;
• a transmitting module:
• and
• a processor,
• wherein the processor is configured to:
• control the receiving module to receive downlink control information (DCI) through a downlink control channel,
• wherein the DCI includes resource assignment information for downlink data, and
• wherein the DCI includes a new data indicator (NDI) for each of a first transport block and a second transport block;
• and
• control the receiving module to receive the downlink data through a downlink data channel based on the resource assignment information, the downlink data including at least the first transport block or the second transport block,
• wherein, if the first transport block or the second transport block is disabled, one layer among a first layer and a second layer is used for transmission of an enabled transport block,
• wherein a 1-bit NDI of the disabled transport block included in the DCI indicates the one layer used for the transmission of the enabled transport block.

A base station for transmitting a downlink signal to a user equipment, the base station comprising:

• a receiving module;
• a transmitting module;
• and
• a processor,
• wherein the processor is configured to:
• control the transmitting module to transmit downlink control information (DCI) through a downlink control channel,
• wherein the DCI includes resource assignment information for downlink data, and
• wherein the DCI includes a new data indicator (NDI) for each of a first transport block and a second transport block;
• and
• control the transmitting module to transmit the downlink data through a downlink data channel in accordance with the resource assignment information, the downlink data including at least the first transport block or the second transport block,
• wherein, if the first transport block or the second transport block is disabled, one layer among a first layer and a second layer is used for transmission of an enabled transport block,
• wherein a 1-bit NDI of the disabled transport block included in the DCI indicates the one layer used for the transmission of the enabled transport block.