Improving performance of coherent coded OFDM systems using space time transmit diversity

The performance gain of space time transmit diversity (STTD) for coded OFDM systems using space time block coding (STBC) is investigated. In particular, it is proposed to use pilot patterns, which are orthogonal in both the frequency and time directions. Therefore, to obtain channel estimates from the separate transmit antennas the receiver can use either adjacent pilots in the frequency direction or adjacent pilots in the time direction.