Patent ID: 8908494

Claim:
A method of transmitting a signal at a base station in a wireless communication system, the method comprising: transmitting a preamble including a modulation sequence, the modulation sequence being indexed as one of 0 to 2N−1, wherein the index of the modulation sequence is used to determine a cell identifier and N is a number of pre-defined hexadecimal sequences, wherein, if the index of the modulation sequence is within 0 to N−1, the modulation sequence is obtained by modulation of one of the pre-defined hexadecimal sequences, and wherein, if the index of the modulation sequence is within N to 2N−1, the modulation sequence is obtained by using the following equation: v k (q) =( v k (q-N) )* (for N≦q≦ 2 N− 1) where v k (q) is a k th modulation symbol in a modulation sequence of index q, v k (q-N) is a k th modulation symbol in a modulation sequence of index (q−N), k is an integer greater than or equal to 0, and the symbol “*” represents a conjugate operation.