A user equipment (UE) transmits uplink control information (UCI) and a base station receives UCI when the UE is configured to have a number of cells configured for operation with carrier aggregation (CA). The base station configures the UE with a code rate and the UE determines a maximum UCI payload to transmit in a subframe that results in a transmission code rate that is no larger than the configured code rate. For transmission of aperiodic channel state information (A-CSI), a number of triggering states depends on the number of cells.