Because of using orthogonal antennas, it receives signal which from all-round is strongest intensity.

Orthogonal frequency division multiplexing (OFDM), single carrier frequency domain equalization (SC-FDE) and multiple antennas technique are efficient techniques to achieve this goal.

So we put forward an orthogonal method which can be used to design the STTC with large number of transmit antennas and avoid the complicated search for the code.