A method and device for transmitting a frame of a wireless communication begins by generating a preamble of the frame that includes a short training sequence and at least one long training sequence. The at least one long training sequence includes non-zero energy on each of a plurality of subcarriers except a DC subcarrier. The at least one long training sequence corresponds to the number of antennas and applicable wireless communication standards. A matrix is defined to represent the at least one long training sequence. The preamble is compatible with legacy and current standards. A channel is defined with a set of sub carriers to transmit the frame.