Rank feedback method for multiple-input multiple-output transmission

A method for reporting a plurality of control information in a wireless mobile communication system using a plurality of transmit antennas, the method comprising:

• transmitting first control information;
• and transmitting second control information, wherein the transmission of the first control information and the transmission of the second control information are performed in units of one subframe and are performed once per predetermined period, respectively, and both of the first control information and the second control information is transmitted through a physical uplink control channel (PUCCH),
• wherein, when the wireless mobile communication system operates in a closed-loop spatial multiplexing mode, the first control information is rank information (RI), and the second control information is information as to a wideband channel quality indicator (CQI) and a wideband precoding matrix index (PMI),
• wherein, when the wireless mobile communication system uses two transmit antennas, four bits are allocated for transmission of the wideband CQI if a rank is 1, and seven bits are allocated for transmission of the wideband CQI if a rank is greater than 1, and wherein, when the wireless mobile communication system uses four transmit antennas, four bits are allocated for transmission of the wideband CQI if a rank is 1, and seven bits are allocated for transmission of the wideband CQI if a rank is greater than 1.