Patent ID: 7881396

Claim:
A method of receiving a preamble in an orthogonal frequency division multiplexing (OFDM) communication system using Q receiving antennas, comprising the steps of: receiving a preamble, the preamble being generated by: generating a base preamble sequence including a cyclic prefix (CP) and an orthogonal sequence; and generating a preamble sequence for each of the Q receiving antennas from the base preamble sequence by rotating the orthogonal sequence of the base preamble sequence by a different predetermined number of symbols, and at least twice receiving the generated preamble sequences, such that the preamble sequence received at a kth antenna is (−1) (PS-1) S(t−(k−M−1)T/M), wherein M is a predetermined number, k is greater than M, S(t) is the orthogonal sequence, T is the period of the orthogonal sequence, and PS is an index indicating a transmission period of the preamble sequence.