A base station includes a transmit path circuitry to transmit an uplink grant to a subscriber station. The uplink grant indicating a first MCS value for a first codeword transmission and a second MCS value for a second codeword transmission. The base station also includes a receive path circuitry configured to receive a MIMO uplink subframe from the subscriber station, the MIMO uplink subframe having a first subset of layers used for the first codeword transmission and a second subset of layers used for the second codeword transmission. ACK/NACK information and RI information are repeated on both the first and second subsets of layers, and CQI is spatially multiplexed on either the first subset or the second subset of layers. If the first MCS value is different from the second MCS value, the CQI is spatially multiplexed onto the subset of layers having a higher MCS value.