A communication device includes a processor that executes a process including: detecting a plurality of zero-cross samples each having a different plus-minus sign from a sign of an adjacent sample from among a plurality of samples obtained by oversampling a received signal; changing positions of the detected zero-cross samples to positions inside a window referring to a position of a reference zero-cross sample selected from the detected zero-cross samples; calculating an average value of relative distances between the reference zero-cross sample and the zero-cross samples, after the positions of the zero-cross samples are changed at the changing; and determining a zero-cross point serving as a reference point for estimating a peak position of the received signal, based on the calculated average value of the relative distances and the reference zero-cross sample.