Method for generating downlink frame, and method for searching cell

A recording medium for recording a program for performing a method of generating a downlink frame including a first synchronization signal and a second synchronization signal, the method comprising:

• generating a first short sequence and a second short sequence indicating cell group information;
• generating a first scrambling sequence determined by the first synchronization signal;
• generating a second scrambling sequence determined by the first short sequence;
• scrambling the first short sequence with the first scrambling sequence, and scrambling the second short sequence with at least the second scrambling sequence;
• and
• mapping a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence in the frequency domain.

A method for identifying a cell in a terminal of a communication system in which a plurality of cells are divided into a plurality of cell groups, and each of the cell groups includes at least two cells, the method comprising:

• receiving a first synchronization signal, the first synchronization signal being determined by a cell identifying sequence number for identifying a cell within a cell group;
• and
• receiving a second synchronization signal including a first short sequence scrambled with a first scrambling sequence and a second short sequence scrambled with at least a second scrambling sequence,
• wherein the first short sequence and the second short sequence are determined by a cell group number for identifying a cell group,
• the first scrambling sequence depends on the first synchronization signal,
• the second scrambling sequence depends on the first short sequence, and
• the terminal identifies a cell based on the cell group number and the cell identifying sequence number.