A method for transmitting and receiving signals using multi-band Radio Frequencies (RFs) is provided. The method performs channel coding on an information unit of a specific layer above a physical layer to produce a specific number of codewords and maps the generated specific number of codewords to a plurality of frequency allocation bands managed by one specific layer, and then transmits the mapped signal through each of the plurality of frequency allocation bands. Each of the plurality of frequency allocation bands managed by the one specific layer has a band size for allocation for a specific service according to a predetermined frequency policy. When the generated specific number of codewords is mapped to the plurality of frequency allocation bands, each of the specific number of codewords is mapped to at least one of the plurality of frequency allocation bands. A frequency allocation band used for transmission of each codeword when the codeword is retransmitted may be set to be different from that when it is initially transmitted.