A wireless communication base station apparatus wherein when a frequency scheduling transmission and a frequency diversity transmission are performed in a multicarrier communication at the same time, the adaptive control of a channel for performing the frequency scheduling transmission can be prevented from being complicated. In this apparatus, a modulating part (12) modulates an encoded Dch data to generate Dch data symbols. A modulating part (22) modulates an encoded Lch data to generate Lch data symbols. An assigning part (103) assigns the Dch and Lch data symbols to subcarriers constituting OFDM symbols and outputs them to a multiplexing part (104). At this moment, the assigning part (103) assigns a set of Dch and Lch data symbols to each subcarrier for a respective subband.