A method for receiving a downlink signal from a base station to a user equipment in a multiple input multiple output, MIMO, system that supports dual layer transmission based on first and second antenna ports, the method comprising: receiving, by the user equipment, downlink control information, DCI, through a downlink control channel; and receiving, by the user equipment, downlink data through a downlink data channel, the downlink data including one or more of a first transport block and a second transport block, wherein the downlink control information includes a new data indicator, NDI, for each of the first and second transport blocks, characterized in that: when the downlink control information indicates that the first transport block is disabled and the second transport block is enabled, the new data indicator for the disabled first transport block indicates an antenna port through which the enabled second transport block is received, when the downlink control information indicates that the first transport block is enabled and the second transport block is disabled, the new data indicator for the disabled second transport block indicates an antenna port through which the enabled first transport block is received, a transport block to codeword swap flag field is undefined in the downlink control information, when the downlink control information indicates that the first transport block is disabled and the second transport block is enabled, the enabled second transport block is mapped to a first codeword, when the downlink control information indicates that the first transport block is enabled and the second transport block is disabled, the enabled first transport block is mapped to the first codeword, and in that the first and second antenna ports correspond, respectively, to first and second layers for the dual layer transmission of the first and second transport blocks. receiving, by the user equipment, downlink control information, DCI, through a downlink control channel; and receiving, by the user equipment, downlink data through a downlink data channel, the downlink data including one or more of a first transport block and a second transport block, wherein the downlink control information includes a new data indicator, NDI, for each of the first and second transport blocks, characterized in that: when the downlink control information indicates that the first transport block is disabled and the second transport block is enabled, the new data indicator for the disabled first transport block indicates an antenna port through which the enabled second transport block is received, when the downlink control information indicates that the first transport block is enabled and the second transport block is disabled, the new data indicator for the disabled second transport block indicates an antenna port through which the enabled first transport block is received, a transport block to codeword swap flag field is undefined in the downlink control information, when the downlink control information indicates that the first transport block is disabled and the second transport block is enabled, the enabled second transport block is mapped to a first codeword, when the downlink control information indicates that the first transport block is enabled and the second transport block is disabled, the enabled first transport block is mapped to the first codeword, and in that the first and second antenna ports correspond, respectively, to first and second layers for the dual layer transmission of the first and second transport blocks. when the downlink control information indicates that the first transport block is disabled and the second transport block is enabled, the new data indicator for the disabled first transport block indicates an antenna port through which the enabled second transport block is received, when the downlink control information indicates that the first transport block is enabled and the second transport block is disabled, the new data indicator for the disabled second transport block indicates an antenna port through which the enabled first transport block is received, a transport block to codeword swap flag field is undefined in the downlink control information, when the downlink control information indicates that the first transport block is disabled and the second transport block is enabled, the enabled second transport block is mapped to a first codeword, when the downlink control information indicates that the first transport block is enabled and the second transport block is disabled, the enabled first transport block is mapped to the first codeword, and in that the first and second antenna ports correspond, respectively, to first and second layers for the dual layer transmission of the first and second transport blocks.