A method for transmitting Downlink Control Information DCI when a cyclic redundancy check code in a downlink control channel is scrambled with a Semi-Persistently Scheduled Cell Radio Network Temporary Identifier SPS C-RNTI, the method comprising: generating DCI by a base station according to DCI Format 1A that is used for indicating a transmission scheme of corresponding Physical Downlink Shared Channel PDSCH of DCI; receiving, by a user equipment, the DCI and acquiring the DCI according to the DCI Format 1A; wherein the transmission scheme is a single-layer transmission scheme, or a transmission scheme simultaneously involving a single-layer transmission and transmit diversity; wherein the single-layer transmission scheme is a single-antenna-port transmission scheme; said method characterized in that: when the transmission scheme as indicated by the DCI Format 1A is the single-layer transmission scheme, an antenna port corresponding to the layer is a fixed antenna port; wherein the fixed antenna port is antenna port 7; or when the transmission scheme as indicated by the DCI Format 1A is a transmission scheme simultaneously involving a single-layer transmission and transmit diversity, the DCI Format 1A further comprises signaling for indicating whether the current transmission scheme is a single-layer transmission scheme or a transmit diversity transmission scheme, and for indicating an antenna port in the case of a single-layer transmission. generating DCI by a base station according to DCI Format 1A that is used for indicating a transmission scheme of corresponding Physical Downlink Shared Channel PDSCH of DCI; receiving, by a user equipment, the DCI and acquiring the DCI according to the DCI Format 1A; wherein the transmission scheme is a single-layer transmission scheme, or a transmission scheme simultaneously involving a single-layer transmission and transmit diversity; wherein the single-layer transmission scheme is a single-antenna-port transmission scheme; said method characterized in that: when the transmission scheme as indicated by the DCI Format 1A is the single-layer transmission scheme, an antenna port corresponding to the layer is a fixed antenna port; wherein the fixed antenna port is antenna port 7; or when the transmission scheme as indicated by the DCI Format 1A is a transmission scheme simultaneously involving a single-layer transmission and transmit diversity, the DCI Format 1A further comprises signaling for indicating whether the current transmission scheme is a single-layer transmission scheme or a transmit diversity transmission scheme, and for indicating an antenna port in the case of a single-layer transmission. when the transmission scheme as indicated by the DCI Format 1A is the single-layer transmission scheme, an antenna port corresponding to the layer is a fixed antenna port; wherein the fixed antenna port is antenna port 7; or when the transmission scheme as indicated by the DCI Format 1A is a transmission scheme simultaneously involving a single-layer transmission and transmit diversity, the DCI Format 1A further comprises signaling for indicating whether the current transmission scheme is a single-layer transmission scheme or a transmit diversity transmission scheme, and for indicating an antenna port in the case of a single-layer transmission.