On the transmitting side, a decision is made as to whether to add pilot symbols which are separate from basic pilot symbols, to frames, based on the propagation path state, and when symbols are added, control symbols comprising information relating to the additional pilot symbols are generated, and frames comprising basic pilot symbols, control symbols, additional pilot symbols, and data symbols are assembled and transmitted. On the receiving side, control symbols included in the received frames are demodulated, and a judgment is made as to whether additional pilot symbols are included in the received frames based on the control symbol information, and if additional pilot symbols are included, the additional pilot symbols are used to estimate the propagation path, and the propagation path estimation value is used to demodulate data symbols.