US Patent 7672385 Radio apparatus

A modem unit inputs a combination, of control signal and data signal, which is to use a plurality of subcarriers. Among a plurality of combinations inputted, the modem unit performs interleaving with a size defined by the first number of subcarriers on a control signal and performs interleaving with the size defined by the second number of subcarriers on a data signal. The modem unit appends additional signals to control signals contained in the second and the subsequent combinations in a plurality of combinations interleaved. The modem unit appends additional signals whose number of subcarriers is equal to the difference between the first number of subcarriers and the second number of subcarriers.