A radio communication apparatus includes a receiving unit configured to receive signals, an obtaining unit configured to obtain a reference amplitude that depends on a modulation scheme for a received signal received by the receiving unit, and on amplitude fluctuations of the received signal in a propagation path, a demodulating unit configured to demodulate the received signal to obtain an in-phase component and a quadrature component of each received symbol included in the received signal, a calculating unit configured to calculate a likelihood ratio for each of bits mapped to each received symbol using the reference amplitude and the in-phase or quadrature component, and a decoding unit configured to perform error correction decoding on the received signal using the calculated likelihood ratios.