Method and apparatus for generating preamble in broadband wireless communication system using multiple antennas

The present invention changes the preamble structure in the broadband wireless communication system using multiple antennas as for the preamble generating method for improving transmit diversity, which is a wireless communication system using multiple antennas based on MIMO (Multiple Input Multiple Output) a method for generating a preamble from, each other, selecting a first pilot tone corresponding to a different antenna, according to the frequency axis in the process, which is multiplied by the different first Walsh code for each of the first pilot tones, and the same antenna second pilot selecting a tone in this order, and the step of forming the preamble by assigning the second step, which is multiplied by the second Walsh code for the pilot tones, respectively, and the first and the output became 2 Walsh code is multiplied by the signal for more than one symbol interval and including, for the at least two symbol intervals a series of pilot tones for each section It is characterized by multiplying the code sequence by alternating the first and second Walsh code while leaving a gap of as much as one pilot tone in each section. The preamble structure of the present invention is produced through the above-described structure is a structure having the orthogonality between antennas by use of the three areas, and the frequency, time and code. Preamble structure, a transmission antenna diversity (Transmit antenna diversity), code orthogonality (Orthogonality), multiple antennas