A method for allocating a subchannel in a transmitter of an Orthogonal Frequency Division Multiple Access (OFDMA) cellular communication system in which an entire frequency band includes a plurality of bands, each of the bands includes a plurality of bins, and each of the bins includes a plurality of subcarriers. The method includes dividing a predetermined time interval into an Adaptive Modulation and Coding (AMC) subchannel time interval and a diversity subchannel time interval; selecting any one of the plurality of bands in the AMC subchannel time interval; selecting a predetermined number of bins among the plurality of bins in the selected band; and allocating the selected bins to the AMC subchannel.