A first communication apparatus configured to transmit OFDM signals by using at least some of a plurality of frequency sub-channels on a frequency band, each of the OFDM signals comprising OFDM symbols for a first time slot and OFDM symbols for a second time slot, wherein the first time slot is a control slot and the second time slot is a data slot, the first communication apparatus comprising: a transmitting circuit configured for transmitting the OFDM signals to a second communication apparatus by using a plurality of subcarriers allocated among an even number of contiguous frequency sub-channels that can be used simultaneously by the second communication apparatus, wherein the even number comprises at least an even number smaller than a number of the plurality of frequency sub-channels on the frequency band; the first communication apparatus is characterized by further comprising a processing circuit configured for: allocating data for constructing each of the OFDM symbols for the first time slot to a first subset of subcarriers of the plurality of subcarriers without allocating data at least to each of respective subcarriers positioned in respective centers of frequency sub-channels among the even number of the contiguous frequency sub-channels, and allocating data for constructing each of the OFDM symbols for the second time slot to a second subset of subcarriers of the plurality of subcarriers without allocating data to a subcarrier positioned in a center of a frequency band of the even number of the contiguous frequency sub-channels for the second time slot, the unused subcarrier being in a center between contiguous frequency sub-channels, the second subset of subcarriers comprising the respective subcarriers positioned in respective centers of frequency sub-channels among the even number of the contiguous frequency sub-channels, wherein the data for transmission in the first time slot to be allocated to the first subset of subcarriers of the plurality of subcarriers that are allocated among the even number of the contiguous frequency sub-channels comprises data representing control information. a processing circuit configured for: allocating data for constructing each of the OFDM symbols for the first time slot to a first subset of subcarriers of the plurality of subcarriers without allocating data at least to each of respective subcarriers positioned in respective centers of frequency sub-channels among the even number of the contiguous frequency sub-channels, and allocating data for constructing each of the OFDM symbols for the second time slot to a second subset of subcarriers of the plurality of subcarriers without allocating data to a subcarrier positioned in a center of a frequency band of the even number of the contiguous frequency sub-channels for the second time slot, the unused subcarrier being in a center between contiguous frequency sub-channels, the second subset of subcarriers comprising the respective subcarriers positioned in respective centers of frequency sub-channels among the even number of the contiguous frequency sub-channels, allocating data for constructing each of the OFDM symbols for the first time slot to a first subset of subcarriers of the plurality of subcarriers without allocating data at least to each of respective subcarriers positioned in respective centers of frequency sub-channels among the even number of the contiguous frequency sub-channels, and allocating data for constructing each of the OFDM symbols for the second time slot to a second subset of subcarriers of the plurality of subcarriers without allocating data to a subcarrier positioned in a center of a frequency band of the even number of the contiguous frequency sub-channels for the second time slot, the unused subcarrier being in a center between contiguous frequency sub-channels, the second subset of subcarriers comprising the respective subcarriers positioned in respective centers of frequency sub-channels among the even number of the contiguous frequency sub-channels, wherein the data for transmission in the first time slot to be allocated to the first subset of subcarriers of the plurality of subcarriers that are allocated among the even number of the contiguous frequency sub-channels comprises data representing control information.