Techniques for transmitting control information to support communication on multiple component carriers (CCs) are disclosed. A user equipment (UE) may be configured for operation on multiple CCs. These CCs may be associated with control messages having different definitions. For example, a control message for a CC configured for frequency division duplex (FDD) may have a different definition than a control message for a CC configured for time division duplex (TDD). A base station may send first control information for a first CC based on a definition of a control message for a second CC, instead of a definition of a control message for the first CC. The control message for the second CC may be selected for use to send the first control information based on various designs.