Method and apparatus for transmitting signals for multiple input multiple output wireless communication system

A transmitting method comprising:

• generating at least one or the other of (1) a first packet signal, which is transmitted from a plurality of antennas, having a first packet format which includes a first short training sequence (STS) for a MIMO system and a first long training sequence (LTS) for the MIMO system, the first STS and the first LTS being arranged in that order in the first packet format, and (2) a second packet signal, which is transmitted from a plurality of antennas, having a second packet format which includes a second STS for a non-MIMO system, a second LTS for the non-MIMO system, and a third LTS for the MIMO system, the second STS, the second LTS, and the third LTS being arranged in that order in the second packet format;
• and
• transmitting the generated one of the first and second packet signals, wherein
• the first packet format includes no second LTS,
• the first and second STSs are for AGC estimation,
• the first to third LTSs are for channel estimation,
• the first LTS has a signal pattern which is the same as that of the third LTS, and
• the first STS has a signal pattern which is different from that of the second STS.