Channel state information is reported in periodic and aperiodic reports for multiple component carriers or serving cells. Channel state information may be reported for a subset of aggregated downlink carriers or serving cells. For an aperiodic report, the carrier(s)/serving cell(s) for which channel state information is reported are determined based on the request for the aperiodic report. When a CQI/PMI/RI report and a HARQ ACK/NACK report coincide in a subframe, the HARQ ACK/NACK report is transmitted on PUCCH, and the CQI/PMI/RI report is transmitted on PUSCH.