generated from the generator and a receiver to receive the reception signal on the basis of the plurality of sets of diffusion codes generated from the generator the generator generates the sync code in a manner such that the cross correlation values are set to very small values at positions near a code sync point or are enough smaller than the autocorrelation peak of the sync code or are set to very small values at both of or either one of the positions before and after the code sync point application_number US 24793794 A description in the following embodiments as diffusion codes there are used a plurality of orthogonal codes in which even cross correlation values for sync channels are set to 0 at positions near a code synchronization point particularly at the positions of at least two chips before and after such a code sync point or at the position of one chip before or after such a point when the even cross correlation values are equal to 0 at the positions near the code sync point odd cross correlation values cross correlation values in the case where transmission data is inverted such as 0 u2192 1 or 1.