A method of receiving uplink control information is provided at a communication apparatus configured with a plurality of cells including a first cell and a second cell in a wireless communication system. A first set of one or more Physical Downlink Shared Channel (PDSCH) signals is transmitted within M downlink subframes through the first cell, where M≧1. A second set of zero or more PDSCH signals is transmitted within N downlink subframes through the second cell, where N≧1. The communication apparatus receives acknowledgment information on an uplink subframe, the acknowledgment information including acknowledgment information for the first set and acknowledgment information for the second set.