Patent ID: 8009760

Claim:
A method of transmitting downlink channels at a base station of an orthogonal frequency division multiplexing (OFDM) system, the method comprising: transmitting first information indicating a size m of a first region through a broadcast channel, wherein the first region is defined by m OFDM symbol(s) starting from a beginning of a subframe and the first region is used for first channels that carry hybrid automatic repeat request (HARQ) ACK/NACKs; transmitting second information indicating a size n of a second region through a physical control format indicator channel (PCFICH), wherein the second region is defined by n OFDM symbol(s) starting from the beginning of the subframe and the second region is used for second channels that carry downlink control information; and transmitting the HARQ ACK/NACKs and the downlink control information through the first channels and second channels, respectively, wherein first resources for the first channels are identified from the first information, and second resources for the second channels are identified from remaining resources excluding the first resources within the second region, and wherein the second channels are physical downlink control channels (PDCCHs).