A method of receiving uplink control information at a communication apparatus in a wireless communication system configured for Time Division Duplex (TDD) operations and having a plurality of cells is described. A first set of at least one of one or more Physical Downlink Control Channel (PDCCH) signals and one or more Physical Downlink Shared Channel (PDSCH) signals are transmitted within M downlink subframes, where M≧1. A second set of at least one of one or more PDCCH signals and one or more PDSCH signals are transmitted within N downlink subframes, where N≧1. Acknowledgment information is received on an uplink subframe, the acknowledgment information including first acknowledgment information corresponding to the first set and second acknowledgment information corresponding to the second set.