FIELD: radio engineering. SUBSTANCE: invention can be employed in CDMA mobile communication systems to form complex quasi-orthogonal codes and to expand channel data with the aid of formed complex quasi-orthogonal codes. Method includes formation of M sequence with length N and of special sequence displaying good complete correlation with M sequence, formation of preset number of other special sequences by way of cyclic shift of M sequence and rearrangement of columns of cyclically shifted special sequences in the same manner as rearrangement of columns for conversion of formed M sequences to orthogonal Walsh codes to generate masks-candidates, formation of specimens of quasi-orthogonal codes by operating on masks-candidates and orthogonal Walsh codes having same length as masks-candidates, selection of quasi- orthogonal codes proceeding from formed specimens of quasi-orthogonal codes and partial correlation between various quasi-orthogonal codes and selection of masks suitable for formation of selected quasi-orthogonal codes. EFFECT: raised carrying capacity of communication channels in CDMA communication systems. 19 cl, 22 dwg
