Encoding and modulating method, and decoding method for wireless communication apparatus

A receiver that receives a train of symbols into each of which a predetermined number of bits, that is, k bits are converted, and each of which is produced by thinning duplicate bits, which are produced by iteratively encoding the predetermined number of bits by dv times of iteration, into m bits (m<l) in units of l bits, and allocating the m bits to one symbol, comprising:

• a symbol demapper that outputs first external information using a received symbol and pieces of a priori information on (m−1) bits;
• a check-node decoder that outputs second external information on one bit using the pieces of first external information on m bits, which constitute the received symbol, outputted from the symbol demapper, and pieces of a priori information on (l−1) bits;
• a deinterleaver that deinterleaves the pieces of second external information on a plurality of bits included in the symbol;
• a variable-node decoder that outputs third external information on one bit using the pieces of second external information on (dv−1) bits, which are outputted from the deinterleaver, as pieces of a priori information;
• and
• an interleaver that performs interleaving, which is a reverse of processing performed by the deinterleaver, on the pieces of third external information on duplicate bits which are outputted from the variable-node decoder, wherein
• the check-node decoder outputs pieces of fourth external information on the m bits using the pieces of third external information on the l bits, which are outputted from the interleaver, as pieces of a priori information;
• and
• the pieces of fourth external information are used as pieces of a priori information by the symbol demapper.