Patent ID: 7372910

Claim:
An apparatus for generating a preamble sequence in an orthogonal frequency division multiplexing (OFDM) communication system using A subcarriers in a frequency domain, the apparatus comprising: a preamble sequence generator for generating a length−M+N+k preamble sequence, where M+N+k is less than A, by combining a length−N Golay complementary sequence with a length−M Golay complementary sequence, wherein k is an integer larger than a smaller one of−N and −M; and an inverse fast Fourier transform (IFFT) processor for assigning elements constituting the preamble sequence to the M+N+k subcarriers among the A subcarriers, on a one-to-one mapping basis, assigning null data to remaining subcarriers excluding the M+N+k subcarriers from the A subcarriers, and IFFT-transforming the assigned results into time-domain data.