A method of generating a downlink frame (110) including a primary synchronization signal and secondary synchronization signals, comprising: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence and a second scrambling sequence determined by the primary synchronization signal; generating a third scrambling sequence determined by a short sequence group-the wireless communication system uses a plurality of short sequences and the plurality of short sequences are grouped into a plurality of groups of Short- sequence to which is assigned the first short sequence and a fourth scrambling sequence determined by a short sequence group to which is assigned the second short sequence; scrambling the first short sequence with the first scrambling sequence and scrambling the second short sequence with the second scrambling sequence and the third scrambling sequence; scrambling the second short sequence with the first scrambling sequence and scrambling the first short sequence with the second scrambling sequence and the fourth scrambling sequence; and mapping the secondary synchronization signal that includes the first short sequence scrambled with the first scrambling sequence, the second short sequence scrambled with the second scrambling sequence and the third scrambling sequence, the second short sequence scrambled with the first sequence scrambling the first short sequence and the scrambled second scrambling sequence and the fourth scrambling sequence to a frequency domain.