A method for a communication apparatus to transmit an uplink signal in a wireless communication system. The communication apparatus receives a control channel signal including resource allocation information for two or more non-consecutive resource block sets. Each resource block set includes a single resource block group (RBG) or at least two consecutive RBGs. The communication apparatus transmits the uplink signal in accordance with the control channel signal for data transmission. The resource allocation information uses a combinatorial index corresponding to at least four indices to indicate the two or more non-consecutive resource block sets.