Method and apparatus for transmitting training sequence in multi user wireless communication system

A method of transmitting a long training field in a multi-user multiple input multiple output based radio communication system, the method comprising:

• determining at least station transmitting data and the number of transmission stream for the stations;
• combining and remapping transmission streams for each station if it is determined that the remapping of the long training fields is needed through channel status information of each station;
• calculating the number of long training fields corresponding to the number of remapped transmission streams and determining the least common multiple of the number of long training fields;
• and
• allocating the long training fields for each station to correspond to the number of symbols of the determined least common number.

An apparatus of transmitting a long training field in a multi-user multiple input multiple output based radio communication system, the apparatus comprising:

• a station number determination unit configured to determine at least one station to be transmitted using transmission data or channel status information;
• a transmission stream allocation unit configured to determine the number of transmission streams for each of the least one station determined by the station number determination unit;
• a long training field number calculation unit configured to calculate the number of long training fields required for each of the at least one station determined by the transmission stream allocation unit and determines the least common multiple of the number of calculated long training fields;
• and
• a long training field allocation unit configured to allocate the long training fields for each station to subcarriers allocated to each station to correspond to the least common multiple of the determined long training fields.