For certain embodiments, a preamble sequence associated with a particular number of transmit antennas may allow a receiving mobile station to determine the number of transmit antennas used for transmission. The preamble sequence may be selected from one of a set of Constant Amplitude and Zero Auto Correlation (CAZAC) sequences corresponding to all of the supported number of transmit antennas. As a result, a receiving station may be able to determine the sequence sent by correlation and, thereby determine the number of antennas used for transmission. Given the number of transmit antennas, the mobile station may then perform MIMO channel estimation during initial synchronization to recover the channel taps between each transmit and each receive antenna.